NVP in relation to miscarriage in the current pregnancy
26. NVP IN RELATION TO MISCARRIAGE IN THE CURRENT PREGNANCY
- The significant relationship between NVP and miscarriage is a reverse one i.e. the more severe the nausea and vomiting the less tendency to abort. 100 women, 11 miscarried. (4)
- Gravidae who do not experience NVP in the first trimester have higher abortion rates. 1,910 normal births, 27.1% no NVP, 126 miscarriages, 46.5% no NVP. (5)
- There is a lower frequency of NVP in pregnancies resulting in spontaneous abortion. 855 singleton deliveries, 56 abortions. Frequency of emesis in pregnancies with different outcomes, Infants 70%, Spontaneous Abortions 50%. (6)
- Hyperemesis gravidarum patients did not have any increased incidence of spontaneous abortion compared with the general obstetric population. (10)
- Women who do not suffer nausea in early pregnancy experience abortion rates nearly three times as high as gravidas who experience NVP in early pregnancy. 4,277 gravidas. (12)
- A deficit of prescriptions of anti-histamine (anti-emetic drugs) in women whose pregnancies ended in abortion was found in the Royal College of General Practitioners’ Research Unit Outcome of Pregnancy study, conducted between 1967 and 1968, suggesting that emesis gravidarum is associated with a good prognosis for pregnancy. 9,147 pregnancies. (D M Fleming, personal communication).
- 591 (11.9%) patients used anti-emetics out of a total patient population of 4,954 who had living normal infants, but of 423 women who later had a miscarriage, only 22 (5.2%) used anti-emetics. (16)
- Among pregnancies carried to at least 14 weeks there were 153 miscarriages (3.4%) among the vomiting group total vomiting 4,517 pregnancies, and 184 (5.3%) among the non-vomiting group, total 3,502 pregnancies in the non-vomiting group. (18)
- Women with no symptoms of NVP experienced a significantly greater proportion of fetal deaths. 414 pregnancies, 44 women had no NVP. (21)
- Women with hyperemesis (419) had fewer spontaneous abortions than women who did not vomit (836). 6/419 (1.43%) hyperemesis, 25/836 (2.99%) controls. (22)
- A statistical re-analysis confirmed the decreased risk of miscarriage associated with gestational NVP. The meta-analysis also revealed that 150 additional possibly unreported studies with contradictory evidence would be required to refute this observed association. Meta-analysis included 7 studies based on 18,464 pregnancies of 17,760 women. (30)
- The analysis indicated that vomiting was associated with decreased risk of miscarriage (P)
- 32 women miscarried and were therefore excluded from the main study. Of those 32 miscarriages, 50% were associated with no symptoms of pregnancy sickness, whereas of 363 women in the main study, 19.6%, had no NVP (Gadsby, 1993, not published).
- The risk of spontaneous abortion was higher in women who were not nauseated at all during pregnancy. 1,553 (a 20% sample of 7,767 pregnancies) singleton live births 29.9% no NVP. 450 miscarriages 41.1% no NVP. (51)
- In the 164 women in the study with hyperemesis gravidarum the risk of spontaneous abortion was 3.1% compared to a prevalence of 15% in previously reported populations (P)
- 30 women with hyperemesis gravidarum causing a weight loss of greater than 5% of their pre-pregnancy weight had a spontaneous abortion rate of 2 (6.6%) compared to prevalence of 15% in the previously reported populations. (42)
- Women with spontaneous abortions: 52% nauseated, 46.4% no nausea; 607 women had spontaneous abortions. Controls 1,284 women: 71.7% nauseated; 28.3% not nauseated. (43)
- For the 160 women who completed the study, 74% reported nausea. Of the 20 who miscarried and for whom data are available (n=14), 70% reported nausea. (80)
There is a lower occurrence or severity of NVP in pregnancies resulting in spontaneous abortion.
(4) (5) (6) (10) (12) Fleming (16) (18) (21) (22) (30) (42) (43) (44) Gadsby (51) (64) t (80)
1,863 miscarriages involved in these 18 studies. Total: Eighteen References
MORE DETAILED SUMMARY OF NVP AND HG IN RELATION TO MISCARRIAGE
1. Women with HG have a lower risk of abortion. (22) (42) (64)
1a. Women with HG did not have any increased incidence of spontaneous abortion. (10)
2. Increased NVP is associated with less risk of miscarriage. (4) Fleming (16) (30)
3. Increased risk of miscarriage with no NVP. (5) (12) (18) (21) Gadsby (44) (51)
4. Lower frequency of NVP in pregnancies resulting in abortion. (6) (43) (80)
tP value recorded
On average 25% of women who deliver a single normal infant have no symptoms of NVP. (RI 6)
Did you know?
KETONES ARE NOT AN INDICATOR OF DEHYDRATION
Please note this guideline is for moderate to severe NVP symptoms rather than HG
RCOG Green-top Guideline No. 69
The Management of Nausea and Vomiting of Pregnancy and Hyperemesis Gravidarum
BMJ Clinical Update 2018
Management of severe pregnancy sickness and hyperemesis gravidarum
The risk of a baby being born with a congenital abnormality - the difference between relative and absolute risk
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