The edition · Obstetrics & Gynaecology
Mifepristone outperforms levonorgestrel for emergency contraception
A Cochrane review of 87 trials puts mifepristone ahead of levonorgestrel on pregnancies and side effects, at the cost of delayed menses. Plus what parvovirus B19 really costs a pregnancy, and why a small baby at 35 weeks in chronic hypertension should change your surveillance.
The edition in brief
Today's obstetrics and gynaecology desk leads with a Cochrane review of mifepristone for emergency contraception: 87 randomised trials and about 36,000 participants, with low-dose mifepristone under 25 mg reducing pregnancies compared with levonorgestrel (RR 0.73, 95% CI 0.59 to 0.90, high certainty) and mid-dose 25 to 50 mg giving RR 0.67 (0.49 to 0.91, moderate certainty). Side effects were fewer; delayed menses was commoner and dose-related. Seventy-nine of the 87 trials were done in China, which limits how far the side-effect and satisfaction findings travel. A meta-analysis of 44 studies gives the numbers needed to counsel a woman with parvovirus B19 in pregnancy: intrauterine death in 38.7 per cent of confirmed fetal infections but 7.3 per cent of maternal infections, hydrops in 58.7 per cent of infected fetuses, and abnormal neuroimaging in 28.6 per cent of those scanned by fetal MRI. Outcomes in the 2023 to 2024 wave were no worse than earlier waves. A New South Wales record-linkage study of 520,050 first births found uterine surgery before a first birth associated with later preterm birth (adjusted OR 1.51, 1.47 to 1.55) and stillbirth (adjusted OR 1.39, 1.26 to 1.53), strengthening with repeated procedures, though confounding by indication is unresolved. The practice-changer: in 1258 pregnancies with chronic hypertension, only women whose small fetus also had abnormal Dopplers at 35 to 36 weeks went on more often to superimposed preeclampsia and earlier delivery. An estimated fetal weight below the tenth centile on its own did not carry that signal.
Mifepristone beats levonorgestrel on the outcome that counts
Where mifepristone is an option for emergency contraception, it prevents more pregnancies than levonorgestrel with fewer side effects, and the counselling point is the delayed period.
Parvovirus B19: the numbers to counsel with
Quote 7.3 per cent for maternal infection and 38.7 per cent only once fetal infection is confirmed, and keep MCA Dopplers running in between.
Uterine surgery before a first birth, and what follows it
Treat an elective uterine procedure in a woman who has not yet given birth as a decision with obstetric consequences, and say so when consenting her.
Give the pregnancy test a date, not a condition
Write a specific date for the pregnancy test on the packet rather than telling her to test if her period is late.
In chronic hypertension, it is the Dopplers at 35 weeks, not the centile
In a woman with chronic hypertension, abnormal Dopplers at 35 to 36 weeks — not a low centile alone — is the signal to step up maternal surveillance for superimposed preeclampsia.
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