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How long does it last?

Practically everyone from doctors to midwives to pregnancy books and websites will tell you that 'morning sickness' stops at 12 weeks. This has become one of those 'facts' that's repeated so often that you think it must be true. Unfortunately, it's quite a sweeping generalisation - it might be true in some cases, but it can't be used to predict the course of an individual illness. The well known 'fact' that 'morning sickness' stops at 12 weeks isn't even actually true in all cases of moderate Nausea and Vomiting of Pregnancy (NVP), and is certainly untrue for HG. See PSS duration of NVP for a review of the evidence for how long NVP lasts.

When severe NVP and HG are examined separately from mild to moderate NVP, then it becomes apparent that it is a long term illness. A summary of studies shows:

- 32% of 108 women with severe NVP were still suffering symptoms after 20 weeks. (Lindseth et al, 2005)

- In a group of 102 women with HG who were taking large doses of Diclectin, the average week that symptoms stopped was 31.4 +/- 9.5
- In a group of 123 women on the standard dose of Diclectin, (with less severe symptoms), the average week that symptoms stopped was 27.5 +/- 10.4
(Atanackovic et al, 2001)

- Of 201 women with HG, 63% of them had symptoms till birth. (Mullin et al, 2011)

- 45% of women have NVP lasting longer than 30 weeks. HER foundation
(Go to http://www.hyperemesis.org/mothers/current-research/index.php and click on "Duration of HG" poll, then click on view results. 45% of women report that they suffered nausea and vomiting past 30 weeks. Only around 11% of women reported that nausea and vomiting had stopped before 15 weeks.)

- In 88 women with HG, symptoms stopped by 22 weeks in only 9% of cases
- 68% of 88 women with HG reported symptoms till birth
(O'Hara, 2013, OHara 2013 PSS Conference see slide 13)

-In 172 women who have had at least 2 HG pregnancies, 52% in the first pregnancy and 50% in the second pregnancy were still taking antiemetics at birth (O'Hara 2017)

Because HG is likely to last for a very long time, and quite possibly the entire pregnancy, it is even more important to have prompt treatment and a long term treatment plan. It is unacceptable for a woman with HG to be told, 'it will pass' or 'it's normal'. Yes it will pass, but that is no excuse for lack of treatment. The 'it will pass' excuse for not giving medications is ethically questionable and is rarely used in other illnesses. The pain of childbirth is both normal and self-limiting, but pain relief is still offered while it's going on. Many illnesses are self limiting but symptomatic relief is offered in the meantime. 

It is common for women with HG to need medication for the entire pregnancy and this is sometimes resisted by their doctors. Some of them have difficulty in accepting that the patient is genuinely still in need of medication in late pregnancy. This is, in part, due to lack of education about HG and you may have to take on the role of educator for your doctor by pointing him/her to sources of information. When a doctor questions your need for continued medication late into pregnancy, it is easy to think that they don't believe you but they may just not understand how difficult it is for you to carry on your normal life without the medications. Always remember that most doctors have never treated a women with HG, or if they have, they have only seen very few. If your doctor still refuses to treat you despite you having offered them sources of information such as HER FoundationPSS or the documents on this website, you are within your rights to request to be seen by a different doctor. SeeObtaining Treatment  for tips on where to go if your GP refuses medication.

LINSETH, G. AND VARI, P. (2005) Nausea and Vomiting in Late Pregnancy. Health Care for Women International, 26:372-386

ATANACKOVIC, G., NAVIOZ, Y., MORETTI, M. E. & KOREN, G. (2001) The safety of higher than standard dose of doxylamine-pyridoxine (Diclectin (R)) for nausea and vomiting of pregnancy. Journal of Clinical Pharmacology, 41, 842-845.

MULLIN, P. M., CHING, C. Y., SCHOENBERG, F., MACGIBBON, K., ROMERO, R., GOODWIN, T. M. & FEJZO, M. S. Risk factors, treatments, and outcomes associated with prolonged hyperemesis gravidarum. Journal of Maternal-Fetal & Neonatal Medicine, 25, 632-636.

O'HARA, M. E.., Experience of hyperemesis gravidarum in a subsequent pregnancy. Midirs Midwifery Digest, 27:4, 309-318 O'Hara 2017 Midirs