Repeated miscarriages and hormone treatment for infertility give an increased risk of pre-eclampsia among pregnant women.
This comes from a new study from the Norwegian Institute of Public Health. More than 20 000 first-time mothers from the Norwegian Mother and Child Cohort Study (MoBa) were included in the study.
Normal risk
- First-time mothers who had not miscarried or had problems getting pregnant had a 5.2 % risk of pre-eclampsia.
Risk after miscarriage
- Women who had three or more miscarriages had a 50 % increased risk of pre-eclampsia compared with women who had not miscarried.
- Women who had one or two miscarriages are not thought to be at higher risk.
- Among women who had both miscarriages and treatment for infertility, the risk for pre-eclampsia was 13 %.
Risk after infertility treatment
- The study also shows that women who had infertility treatment had a 25 % higher risk of pre-eclampsia.
- Women who became pregnant after hormone treatment to stimulate ovulation had a doubled risk of pre-eclampsia compared to women without treatment.
- Assisted conception treatment was not linked to an increased risk, even though hormone stimulation is part of the procedure.
- Different causes of infertility (polycystic ovary syndrome, blocked Fallopian tubes etc.) can probably explain the difference in risk for pre-eclampsia. It is likely that factors in mothers that cause infertility may also give an increased risk of pre-eclampsia.
- It is less likely that the treatment itself explains the increased risk, even if this cannot be excluded.
The study has been recently published in the British Journal of Obstetrics and Gynaecology , BJOG .
Placenta important for normal development