Possible Preeclampsia Risks After IVF: Navigating Monitoring and Management
May is International Preeclampsia Awareness Month, but any time is a good time for physicians to review preeclampsia risks and learn how to better care for patients who may develop this serious condition.
Patients who are undergoing IVF may have additional questions about the risk of preeclampsia associated with this process. Fertility specialists should stay up to date on the most recent findings regarding this connection so that they may accurately inform patients of the risks while assuaging their concerns as much as possible.
An Overview of Preeclampsia
Preeclampsia is a hypertensive disorder of pregnancy; its two primary characteristics are high blood pressure and proteinuria. The Journal of Pregnancy states that it is most common after 20 weeks gestation, appearing as early onset (before 34 weeks) or late onset (after 34 weeks). This condition affects between 1 percent and 10 percent of pregnancies worldwide and is a leading cause of maternal and fetal morbidity and mortality, with risks that extend into the postpartum period.
According to the International Federation of Gynecology and Obstetrics (FIGO), the highest risk factors for preeclampsia include:
- A history of preeclampsia in a past pregnancy
- Carrying twins or higher-order multiples
- A history of hypertention before the pregnancy
Other conditions that place women at an elevated risk include kidney disease, autoimmune diseases and diabetes. Factors that place women at moderate risk for developing preeclampsia include obesity, advanced maternal age (greater than 35) and a family history of preeclampsia.
Preeclampsia and IVF
A retrospective study published in Placenta in 2020 found that IVF increases the risk of developing preeclampsia, but also accounts for the condition's progression. This study, which compared women undergoing IVF to women with spontaneous conception, found higher rates of severe preeclampsia, first-trimester bleeding and placenta accreta and hypoxia among women conceiving with IVF. Although this study attributes the higher risk of preeclampsia in IVF patients to "defective placentation," the authors did not draw conclusions about why this occurs.
Research published in Hypertension offers an explanation as to how IVF may contribute to higher preeclampsia risks: the corpus luteum — which is absent when frozen embryo transfer or donor eggs are used — may play a crucial role in preeclampsia after IVF. Women who achieved pregnancy without a corpus luteum had higher rates of preeclampsia. As the authors point out, natural pregnancy hormones are artificially replaced in women undergoing IVF, but relaxin — a vasodilator — is not. The corpus luteum releases relaxin during the ovulation process, and this is thought to aid implantation. After the placenta forms, it begins to provide relaxin. The authors theorize that pregnancies achieved without a corpus luteum, and therefore without relaxin, do not have the benefit of vasodilators early in pregnancy.
Detecting and Managing Preeclampsia
Because any pregnant person can develop preeclampsia, it is important to educate patients about the symptoms of this condition, look for early signs and monitor the patient closely. The International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) Practice Guidelines suggest using ultrasound as a screening and prediction tool for preeclampsia. The primary recommendation includes repeated Doppler examination of the uterine arteries. This is done in the first and second trimesters for screening, but only in the third trimester for prediction; Doppler is also not widely available in many areas. The guidelines also caution against relying on ultrasound to assess placental volume.
Ultrasound is always just one facet of screening for preeclampsia, as both ISUOG and FIGO point out, but it is also the primary means of monitoring for fetal complications once preeclampsia has been identified. Possible complications include intrauterine growth restriction and placental abruption.
Although preeclampsia is resolved after delivery, its effects can have lifelong consequences. Research from the American Journal of Renal Physiology reports that women who suffer preeclampsia during pregnancy have both short- and long-term consequences, some of which may be realized up to 15 years later. These include other varieties of hypertension and a "susceptibility to chronic kidney disease."
Until the scientific community better understands the mechanisms leading to preeclampsia, physicians remain unable to offer their pregnant patients a cure. However, knowing which patients are more at risk will enable a physician to be as prepared as possible for the upcoming IVF cycle and prospective pregnancy.
Learn more about pre-eclampsia from GEFOG: Ultrasound in pre-eclampsia and The Role of Ultrasound in Screening for Pre-eclampsia.
