When does morning sickness start? The timeline in early pregnancy

Nausea and vomiting in pregnancy usually begin between the fourth and the seventh week, and for most people who get them they have begun before nine weeks have passed. Most pregnant women feel sick at some point, and many are sick as well, so this is the ordinary course of early pregnancy rather than a complication. The common pattern is a start at around week five or six and a clear easing towards the end of the first trimester. Cleveland Clinic is the only one of the bodies below to name a worst stretch, and it puts it at around weeks eight to ten. Those ranges are wide for a reason. The timing is not set by the calendar. The cause is not fully established, but it is thought to track the hormonal changes of early pregnancy, including the rise of human chorionic gonadotropin, or hCG, and the placental hormone GDF-15.

That is probably why sickness tends to arrive at roughly the same point as a clearly positive test, and why it commonly fades as hCG comes off its peak. This article sets out the shape of it: when it typically begins, when it tends to be at its worst, when it usually eases, and the fact that a meaningful number of people carry it further than that. It also covers what makes sickness more pronounced, why having little or none is not a worrying sign, the measures that help without medicines, and hyperemesis gravidarum, the severe form that is assessed rather than endured.

Why the timing follows the hormonal rise rather than a fixed week

After implantation, the developing placenta starts producing hCG, and the amount in the blood climbs steeply through the early weeks. hCG is measured in mIU/mL, and it is the same hormone a home pregnancy test detects in urine, which is the first clue to the timing of sickness. The test turns clearly positive once hCG has risen past the level the strip can read. Nausea tends to appear in the same window, which is part of why the hormonal rise is thought to be involved.

hCG is not working alone. Oestrogen and progesterone both rise sharply in early pregnancy, progesterone slows the movement of the stomach and the bowel, and the placenta also produces a hormone called GDF-15, which acts on appetite and nausea. RCOG patient information notes that some people get pregnancy sickness far worse than others because of genetic differences that give them higher levels of GDF-15. The honest position is that no single hormone accounts for all of it.

The practical consequence is worth holding on to. hCG does not peak and then stay high. It rises to a maximum in the early weeks and then falls back to a lower level for the rest of the pregnancy. Sickness that begins as hormone levels climb, worsens around their peak and settles as they fall is following a curve, not a date. Two pregnancies that implant a few days apart can therefore start feeling sick a week apart.

The usual shape: when it begins, peaks and eases

RCOG is the only body here that gives a start window in weeks, and it puts it between the 4th and the 7th week. ACOG and Cleveland Clinic frame it differently, saying that for most people it has begun before 9 weeks, and Cleveland Clinic adds that the earliest starts are around the 6th week. Taken together, that is a start in the first two months, most often somewhere between the 4th and the 7th week. The worst stretch is harder to pin down, because only Cleveland Clinic of the sources here gives a figure, and it puts it at around weeks eight to ten. From there, most people improve across the end of the first trimester, and the improvement is often gradual rather than a day when it stops. Keeping an eye on the direction of travel is more useful than counting days.

The last column is the one patients most often read as a promise, and it is not one. A meaningful number of people are still being sick beyond the point their own guidance quotes, some through the second trimester, and a smaller group through to the birth. RCOG, ACOG, Cleveland Clinic and MedlinePlus all say so explicitly, and it is not a sign that something has gone wrong. If you are past the week you were told to expect relief and nothing has changed, that is a reason to say so at your next appointment, not a reason to assume you have been missed.

Vomiting that needs assessment the same day

Most pregnancy sickness is miserable and harmless. A small number of presentations are not, and they are set out here rather than at the end of the article. If you are pregnant or could be and you have severe one sided pain low down, pain at the tip of the shoulder, vaginal bleeding, or you feel faint or collapse, that is an emergency now: call an ambulance or go to an emergency department. An ectopic pregnancy can present with vomiting and is time critical.

Separately from those emergencies, the findings below are not an ambulance matter but do need assessment on the same day rather than at your next appointment.

• Being unable to keep any food or fluid down
• Urine that is very dark, much reduced in amount, or not passing urine at all
• Feeling very weak, dizzy or faint when you stand up, or a racing or pounding heartbeat
• Losing weight, or clothes becoming loose in early pregnancy
• Tummy pain or tenderness alongside the vomiting, which is not a usual part of pregnancy sickness
• A high temperature, shivering, pain or burning on passing urine, or pain in one side of your back or loin, which can mean an infection has reached the kidney
• Vomiting blood, or vomit that looks like coffee grounds

None of those findings means you should wait to see whether tomorrow is better. Contact your midwife, your own doctor or the maternity unit the same day, and if you cannot reach them out of hours, go to the nearest emergency department rather than waiting for the morning. Getting assessed early is what keeps dehydration and weight loss from becoming the larger problem, and it is also what allows a cause other than pregnancy to be found if there is one. A headache alongside vomiting is handled differently depending on how far on you are. From 20 weeks, a headache that is bad or will not go away, with or without flashing lights or blurred vision, pain under the ribs, or new swelling of the face, hands or feet, can be a sign of pre-eclampsia and needs contact with your midwife, your own doctor or the maternity unit the same day, or an emergency department out of hours. Two further patterns are not emergencies but should not be left to the next routine visit either: nausea and vomiting appearing for the first time after the ninth week, and particularly after the sixteenth, and new swelling in the front of the neck. ACOG lists headache, swelling in the front of the neck and first-time sickness after nine weeks among the signs that another cause should be looked for, so raise them with your midwife or doctor rather than waiting for them to pass.

Morning sickness is a misnomer

The name is wrong and every source above says so plainly. Nausea and vomiting in pregnancy can occur at any time of the day or the night, and a good number of people feel sick continuously rather than in an episode. Clinicians generally prefer the term nausea and vomiting of pregnancy, or simply pregnancy sickness, for exactly this reason. If you feel worst in the evening, or in the small hours, or all day without a break, you have ordinary pregnancy sickness and not something unusual.

There is a reason mornings got the blame. An empty stomach after a night without food makes nausea worse, so the first hour of the day is commonly the hardest, and that is also the explanation behind the oldest piece of advice in this field: eat something plain before you get out of bed. But the hormonal drive behind the sickness runs around the clock, which is why a pattern that ignores the morning entirely is just as normal.

What makes pregnancy sickness more likely to be pronounced

Nobody can predict in advance how sick a given person will be, but several things appear on the lists published by the NHS and ACOG, and the first two below appear on RCOG's shorter list as well. They are associations rather than causes, and having several of them does not mean you are certain to be unwell, just as having none is no protection. They are worth knowing mainly because they help you plan: if you recognise yourself in this list, it is reasonable to raise sickness at your first appointment rather than waiting for it.

• A multiple pregnancy, that is twins or more, where hormone levels are higher
• Nausea and vomiting in a previous pregnancy, whether it was mild or severe
• A mother or sister who had severe pregnancy sickness
• A history of motion sickness, for example being carsick or seasick
• A history of migraine
• Having felt sick while taking contraception containing oestrogen
• A first pregnancy
• A body mass index of 30 or more before pregnancy, which appears on the NHS list
• Carrying a female fetus, which appears on the ACOG list

Multiple pregnancy deserves a line of its own because the mechanism is straightforward. A twin pregnancy carries more placental tissue than a single one, whether that is two separate placentas or one shared between the twins, so hCG rises higher and faster, and nausea follows the hormone. This matters after fertility treatment, where a twin pregnancy is more common than it is after natural conception. It does not mean that pronounced sickness indicates twins, and it does not mean a quiet first trimester rules them out. The scan answers that question and the symptoms do not.

Little or no nausea is also common, and is not a warning sign

This is the part most often left out, and it causes a great deal of unnecessary worry. A minority of pregnant women never feel sick at all, and vomiting is a good deal less common than nausea, so most never actually vomit. A substantial number of people go through the first trimester with mild queasiness only, and some have nothing at all. That is a normal version of pregnancy. There is no threshold of sickness a pregnancy has to reach to be progressing properly, and the absence of nausea is not used by any clinician as a sign that something is wrong, because it does not work that way.

ACOG puts the matching point from the other direction: pregnancy sickness usually does not harm the pregnancy, and it does not mean the fetus is unwell. So the symptom does not grade the pregnancy in either direction. If you had sickness and it has stopped at a point the timeline would predict, that is expected. If it stopped abruptly and early and you are anxious about what that means, the reassurance you want comes from a scan and from your own doctor, not from watching your symptoms.

It is also worth saying that sickness varies between pregnancies in the same person. Having had it before does raise the odds of having it again, which is why it appears on the risk lists above, but that is a shift in the odds and not a forecast: MedlinePlus states directly that how much sickness you had in one pregnancy does not predict how you will feel in the next. People who were very unwell the first time are sometimes barely troubled the second, and the reverse happens too. A previous pregnancy tells you something about the odds and very little about what this one will feel like.

What the timing tells you, and what it does not

Because nausea broadly tracks the early hormonal rise, its arrival is a rough marker of where you are rather than of how things are going. Feeling sick at four or five weeks fits the hormone curve and sits alongside the other earliest signs of pregnancy: a missed period, breast tenderness, tiredness out of proportion to the day, passing urine more often, and a sharper sense of smell. What it cannot do is confirm a pregnancy. Only a test can do that, and only a scan can confirm where the pregnancy is sitting.

The reverse question comes up constantly: does sickness that starts early, or that is severe, say anything about hCG levels? Loosely and unhelpfully, yes. Higher hCG is associated with more nausea across groups of people, which is part of why twin pregnancies tend to produce more of it. But the overlap between individuals is so wide that no one can read a hormone level from how sick a person feels, or the reverse. Blood tests are interpreted as numbers with units, in series, by the clinician who ordered them.

One more distinction is worth drawing, because people group digestive symptoms together. Nausea and vomiting are thought to be driven mainly centrally, through the effect of rising hormones on the part of the brain that controls sickness, with slower stomach emptying adding to it. Loose stools are a different mechanism entirely, and as the article on diarrhoea and pregnancy sets out, early pregnancy usually pushes the bowel in the opposite direction. Vomiting fits the pattern of early pregnancy. Diarrhoea does not, and it deserves its own explanation.

Measures that help and are not medicines

There is no single measure that works for everyone, and patient information from the NHS says so openly. What follows is the set of practical things consistently recommended before any medicine is considered. They are simple, they are things most people can try at home, and the honest expectation is that they take the edge off rather than removing the sickness. Try them for several days before deciding whether they are helping, because sickness fluctuates on its own and one bad afternoon is not a verdict.

• Eat little and often, rather than three meals: something every one to two hours keeps the stomach from emptying completely
• Keep something plain by the bed, a dry biscuit or dry toast, and eat it before you get up
• Sip fluids little and often through the day rather than drinking a glass at once, and aim for plenty overall, since ACOG advises drinking water through the day rather than only when you are thirsty
• Favour plain foods higher in carbohydrate and lower in fat: bread, rice, crackers, pasta, potatoes
• Add some protein to each meal where you can, which ACOG and MedlinePlus both suggest: milk, yoghurt, nuts and nut butters, and seeds
• Eat cold food instead of hot if cooking smells set the nausea off, and let somebody else cook where you can
• Avoid the specific smells and foods that trigger you, and keep air moving through the rooms you use
• Ginger, as tea, as a biscuit or in food, has some evidence behind it for nausea
• Rest, because tiredness makes nausea worse, and treat sleep as part of the management rather than a luxury
• Acupressure at the wrist, with a band or with finger pressure, is described as having some evidence
• Keep taking the prenatal vitamin you were advised to take, and if it makes the nausea worse say so rather than stopping it, since ACOG notes that taking a vitamin supplement before and during pregnancy is associated with less severe sickness, and the person looking after your pregnancy can advise on when in the day to take it

Two cautions sit alongside that list. Ginger as a food or a drink is one thing; a concentrated ginger supplement is a product, and the NHS advises checking with a pharmacist before taking such a product in pregnancy. And if you cannot keep fluids down at all, none of these measures is the answer. That is the situation described in the next section, and it needs assessment rather than another dry biscuit.

Hyperemesis gravidarum: the severe form that needs assessment, not endurance

Hyperemesis gravidarum is the most severe form of pregnancy sickness, and the NHS, RCOG and ACOG all describe it that way. The distinction that matters in practice is not the name but where it is managed: ordinary sickness is managed at home, and this is not. The defining feature is vomiting that cannot be brought under control, to the degree that food and fluid do not stay down and normal daily activity stops. ACOG describes a measured loss of weight against the pre-pregnancy weight, a clear drop rather than a small fluctuation, alongside other problems related to dehydration, as the basis on which it may be diagnosed, which is why the weight you started at is worth knowing.

The findings to act on are these: vomiting you cannot control, being unable to keep fluids down, losing weight, passing much less urine than usual or urine that is dark and strong smelling, and feeling weak, dizzy or lightheaded, especially on standing. ACOG adds a racing or pounding heartbeat and being unable to pass urine at all. If that is your situation, contact your midwife, your own doctor or the maternity unit today. This is not something to push through until the next scheduled appointment.

Treatment exists, it is prescribed where assessment shows it is needed, and more than one option is available, so it may take more than one attempt to find what works. Anti-sickness medicines are prescribed in pregnancy, including during the first twelve weeks, and where fluids cannot be kept down, fluid is given directly into a vein in hospital. Which medicine, in which form and for how long is a decision for the clinician who assesses you, and it is deliberately not described here. The useful point is narrower: this is treatable, it is assessed rather than endured, and getting help early can help you avoid dehydration and weight loss.

Hyperemesis does not always follow the timetable of ordinary sickness. It may not settle at 16 to 20 weeks, and some people have symptoms that improve only later in pregnancy or not until the birth. Having had it in a previous pregnancy makes it more likely to recur, and a family history is described in NHS patient information too. If that applies to you, say so early, so that a plan exists before the sickness starts rather than after it has already taken hold.

Why nothing should be started without asking your own doctor

Nothing should be started in pregnancy, including anything bought over the counter, without asking the person looking after your pregnancy first. That covers anti-sickness tablets, herbal preparations, concentrated supplements, and remedies suggested by somebody whose pregnancy went differently. The reason is not that everything on a shelf is unsafe. It is that safety in pregnancy depends on what is being taken, at which stage, and alongside what else, and that judgement belongs to your own doctor, midwife or pharmacist.

Medicines for pregnancy sickness do exist and are prescribed when diet and lifestyle measures are not enough. Patient information describes them as suitable for use in pregnancy, including in the first twelve weeks, and more than one class is available, so a change is possible if the first does not suit you. No names, forms or amounts appear in this article on purpose, because the choice depends on your history and on what else you take, and because something read on a page is not a prescription.

There is a further reason to go through a clinician rather than a shelf. Persistent vomiting sometimes has a cause other than pregnancy, and settling the stomach can delay the question of why the stomach is unsettled. ACOG lists ulcer, food related illness and thyroid or gallbladder disease among the conditions that produce the same symptoms. RCOG advises that other causes be considered, particularly where there is tummy pain, pain on passing urine, or a known ulcer or gallstones.

When sickness starts late or changes character

Timing is also a diagnostic clue, and this is the part of the timeline that gets the least attention. ACOG notes that nausea and vomiting appearing for the first time after the ninth week of pregnancy is a reason to look for another explanation, and RCOG applies the same logic more firmly to vomiting that only begins after sixteen weeks. Pregnancy sickness has a window in which it starts. Sickness that starts outside that window is not automatically something else, but it earns a look.

The same applies to a change in character. Pregnancy sickness is nausea and vomiting without fever, without significant tummy pain and without pain on passing urine. When any of those joins it, the question changes. The NHS notes that urinary tract infections can cause nausea and vomiting, and that an infection of the bladder can travel up to the kidney, which is one of the commoner alternative explanations in pregnancy and is treatable once identified. A less common cause worth naming here, because it follows directly from the hormone argument above, is a molar pregnancy, in which the placental tissue develops abnormally and hCG rises far higher than usual, which can produce sickness out of proportion to the week. It is found on the scan, which is another reason the scan rather than the symptom answers the question.

Tiredness, stress, travel and particular foods are all described as making ordinary sickness worse rather than causing it, and MedlinePlus lists lower blood sugar among the possible contributors to it, so a bad week after a difficult stretch of work is usually just that. The pattern that deserves attention is new sickness late in the first trimester or later, sickness with a feature that does not belong, or sickness that is getting steadily worse when the timeline says it should be improving. Any of those is a conversation with your own doctor rather than a wait.

How sickness fits the timeline after IVF and frozen transfer

After fertility treatment the dates are known rather than estimated, which changes the experience of waiting for symptoms. The transfer date is recorded, so the week of pregnancy is not in doubt, and people often watch for nausea at a precise point on the calendar. The biology does not become more precise just because the dates do. Sickness still follows the hCG rise, so the sensible expectation after a transfer is the same window as anyone else: a usual start in the fourth to the seventh week, with most people affected noticing something before nine.

Two things complicate reading symptoms in a treatment cycle. Progesterone is given as luteal support after transfer, and progesterone can itself produce nausea, breast tenderness and tiredness, so symptoms in the days before a blood test do not distinguish a pregnancy from the support. And a twin pregnancy is more common after treatment, which shifts the odds towards more pronounced sickness. Neither changes the advice: the blood test and the scan decide, and symptoms are read afterwards rather than before.

This article is patient information rather than a treatment plan, and it is not a substitute for the person looking after your pregnancy. If sickness is interfering with your work, your sleep or your ability to look after yourself, that is enough reason to raise it, whatever week you are in and however the timeline above reads. The thresholds in this article are a guide to when to speak up, not a bar you have to clear before you are allowed to.

Related Reading

• Earliest signs of pregnancy: what the hormone timeline actually allows
• Is diarrhoea a sign of pregnancy? What loose stools actually mean
• hCG Levels in Early Pregnancy and After IVF: What the Numbers Mean
• Implantation cramps: what they feel like and what they cannot tell you
• Twins and Multiple Pregnancy in IVF
• Cramps during pregnancy: what is ordinary, what is not, and when to ring

Sources and references

This article is supported by the following independent, authoritative sources:

• NHS, Vomiting and morning sickness
• NHS, Severe vomiting in pregnancy
• RCOG, Pregnancy sickness and hyperemesis gravidarum
• ACOG, Morning sickness: nausea and vomiting of pregnancy
• Cleveland Clinic, Morning sickness
• MedlinePlus, Morning sickness