Risk assessment of hypertensive disorders of pregnancy and other adverse pregnancy outcomes after frozen embryo transfers following an artificial cycle: A retrospective cohort study.

OBJECTIVES: The primary aim was to investigate if frozen embryo transfer (FET) without a corpus luteum increases the risk of hypertensive disorders of pregnancy (HDP). The secondary aim was to investigate other adverse maternal and perinatal outcomes. METHODS: This was a retrospective cohort study of 1168 singleton pregnancies and live births following a FET with either an artificial cycle (AC-FET) (n = 631) or a natural/modified natural/stimulated cycle (CL-FET) (n = 537) between 2012 and 2020. The data were collected from patient records. The primary outcome was HDP. Secondary outcomes included cesarean sections, placental retention problems, postpartum hemorrhage (PPH), the duration of pregnancy, birth weight, low birth weight, macrosomia, length of gestation, preterm birth, small for gestational age, and large for gestational age. RESULTS: In the AC-FET group, there was an increased incidence of pre-eclampsia, gestational hypertension, cesarean sections, PPH over 500 and 1000 mL, and retained placental tissue, compared with the CL-FET group. These associations remained significant in logistic regression analyses with clinically relevant adjustments. CONCLUSION: The risk of HDP and several other maternal complications seems to be increased after AC-FET compared with CL-FET. Our findings support most earlier studies regarding HDP and add to the knowledge on other maternal and perinatal risks involved in AC-FET, including an increased risk of milder forms of placental retention. More studies are needed to confirm these findings.

Clinical features of preeclampsia and hypertensive disorders in pregnancies after different frozen embryo transfer regimens.

OBJECTIVES: To compare whether the clinical features of preeclampsia (PE) or gestational hypertension (GH) were different in pregnancies after a frozen embryo transfer (FET), depending on the FET regimen used. STUDY DESIGN: A retrospective study including 58 pregnancies with PE and 64 pregnancies with GH, all with singleton live births. Pregnancies were stratified according to the presence or absence of a corpus luteum (CL). MAIN OUTCOME MEASURES: Clinical characteristics of PE and GH, maternal background factors, postpartum hemorrhage (PPH), key perinatal outcomes. RESULTS: Among PE patients, no difference was found in the clinical characteristics and in the maternal background factors, when comparing women with a CL to women without a CL. PE patients in the group without a CL had a hemorrhage of > 500 mL or > 1000 mL significantly more often than patients with a CL. Multivariable analyses confirmed this risk. Perinatal outcomes were similar. Among GH patients, there was no difference in the clinical features and maternal background factors, when comparing CL cycles to cycles without a CL. The amount of PPH was higher among the patients without a CL, but the frequency of a > 500 mL or > 1000 mL hemorrhage was similar between groups. No risk increase was seen in multivariable analyses. CONCLUSIONS: Among FET patients with PE, the risk of PPH wasincreased in pregnancies after cycles without a CL, compared to cycles with a CL. The presence or absence of a CL did noteffectthe severity of PE and GH, the duration of pregnancy or blood pressure levels.