Natural ovulation before frozen embryo transfer is as effective as hormone treatment for achieving a healthy baby\u00a0by vitro fertilization (IVF), finds a clinical trial from China published by\u00a0The BMJ\u00a0today.<\/p>\n
Natural ovulation is also linked to a lower risk of several complications for the mother, such as pre-eclampsia (abnormally high blood pressure), the results show.<\/p>\n
Globally, the use of frozen embryo transfer after IVF has increased substantially and accounts for more than 60% of all embryo transfers.<\/p>\n
Doctors prepare the womb lining (endometrium) for frozen embryo transfer most often by either a natural ovulation regimen, which relies on the patient’s own ovulation cycle, or a programmed regimen, which uses hormone drugs (estrogen and progesterone).<\/p>\n
A big question in fertility treatment is which of these methods works best and is safest, but previous trials\u00a0have been unable to\u00a0draw firm conclusions.<\/p>\n
To address this knowledge gap, researchers drew on data for 4,376 ovulatory women (aged 20-40 years) at 24 fertility centres in China who were planning to undergo a frozen single embryo transfer.<\/p>\n
Women were randomised to either a natural ovulation regimen (2,185 patients) or a programmed regimen (2,191 patients) for endometrial preparation and were monitored to determine the ideal timing for embryo transfer.<\/p>\n
The results show that 910 (42%) of patients in the natural ovulation regimen group and 890 (41%) in the programmed regimen group achieved a healthy live birth.<\/p>\n
The risk of pre-eclampsia was also lower in the natural ovulation regimen group among patients who achieved clinical pregnancy compared with the programmed regimen group (2.9%\u00a0v\u00a04.6%).<\/p>\n
And rates of early pregnancy loss (12.1%\u00a0v\u00a015.2%), placental accreta spectrum – when\u00a0the placenta fails to detach easily after birth\u00a0(1.8%\u00a0v\u00a03.6%), cesarean section (69.5%\u00a0v\u00a075.6%), and postpartum haemorrhage – severe bleeding after childbirth (2.0%\u00a0v\u00a06.1%) were all lower in the natural ovulation regimen group.<\/p>\n
No differences between the two groups were seen for birth weight or complications in newborns. The rate of cycle cancellation (stopping treatment) was, however, higher in the natural ovulation group (16.2%\u00a0v\u00a011.5%).<\/p>\n
The researchers acknowledge some limitations that may have biased their results, but say\u00a0this was a large,\u00a0multicentre\u00a0study that\u00a0considered both the effectiveness and safety of mothers and babies, and results were consistent after additional\u00a0analyses, suggesting that they withstand scrutiny.<\/p>\n
As such, they conclude: “The findings of this study suggest that a natural ovulation regimen for endometrial preparation before frozen embryo transfer is as effective as a programmed regimen in terms of a healthy live birth and results in a lower risk of maternal complications during pregnancy.”<\/p>\n
They add: “The findings of this trial may serve as a model for other preconception intervention trials to prevent maternal morbidity and mortality.”<\/p>\n
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