Hypertensive disorders of pregnancy (HDP) is one of the most common pregnancy complications and causes of maternal morbidity and mortality. Assisted reproductive technology (ART) has been associated with adverse pregnancy outcomes, including HDP. However, the impact of multiple pregnancies, oocyte donation, as well as fresh and frozen embryo transfer needs to be further studied. We conducted a systematic review and meta-analyses to evaluate the association between ART and HDP or preeclampsia relative to spontaneous conception (SC).
Methods
We identified studies from EMBASE, MEDLINE, and Cochrane Library (up to April 8, 2020) and manually using structured search strategies. Cohort studies that included pregnancies after in vitro fertilization (IVF) with or without intracytoplasmic sperm fertilization (ICSI) relative to SC with HDP or preeclampsia as the outcome of interest were included. The control group was women who conceived spontaneously without ART or fertility medications. The pooled results were reported in odds ratios (OR) with 95% confidence intervals based on random effects models. Numbers needed to harm (NNH) were calculated based on absolute risk differences between exposure and control groups.
Results
Eighty-five studies were included after a screening of 1879 abstracts and 283 full text articles. Compared to SC, IVF/ICSI singleton pregnancies (OR 1.70; 95% CI 1.60-1.80; I2 = 80%) and multiple pregnancies (OR 1.34; 95% CI 1.20-1.50; I2 = 76%) were both associated with higher odds of HDP. Singleton pregnancies with oocyte donation had the highest odds of HDP out of all groups analyzed (OR 4.42; 95% CI 3.00-6.51; I2 = 83%). Frozen embryo transfer resulted in higher odds of HDP (OR 1.74; 95% CI 1.58-1.92; I2 = 55%) than fresh embryo transfer (OR 1.43; 95% CI 1.33-1.53; I2 = 72%). The associations between IVF/ICSI pregnancies and SC were similar for preeclampsia. Most interventions had an NNH of 40 to 100, while singleton and multiple oocyte donation pregnancies had particularly low NNH for HDP (16 and 10, respectively).
Conclusions
Our meta-analysis confirmed that IVF/ICSI pregnancies are at higher odds of HDP and preeclampsia than SC, irrespective of the plurality. The odds were especially high in frozen embryo transfer and oocyte donation pregnancies.
PMID 34182957 34182957 DOI 10.1186/s12884-021-03938-8 10.1186/s12884-021-03938-8 Chih et al. 2021, Chih 2021
Related articles
assisted-reproduction/safety-and-risks/maternal-complicationspregnancy/pregnancy-complications/hypertensive-disordersbirth-and-delivery/birth-outcomes/maternal-morbidity
Open Access
Almasi-Hashiani A et al., 2019·BMC Pregnancy Childbirth
The objective of this systematic review and meta-analyses was to assess the risk of preeclampsia among women who conceived with assisted reproductive technology (ART). We searched the ISI Web of Knowledge, Medline/PubMed, Scopus, and Embase (from inception to May 2017) for English language articles using a list of key words. In addition, reference lists from identified studies and relevant review articles were also searched. Data extraction was performed by two authors, and the study quality was assessed using the Newcastle-Ottawa Scale. Random-effects model meta-analysis was applied to pool the relative risks (RR) across studies. A total of 48 studies (5 case-control studies and 43 cohort studies) were included in this meta-analysis. The Cochran Q test and I(2) statistics revealed substantial heterogeneity (Q = 26,313.92, d.f. = 47, p < 0.001 and I(2) = 99.8%). Meta-analysis showed a significant increase in preeclampsia in women who conceived by ART compared with those who conceived spontaneously (RR = 1.71, 95% CI = 1.11-2.62, p = 0.015). The findings of this systematic review indicate that the use of ART treatment is associated with a 1.71-fold increase in preeclampsia.
Solmonovich R et al., 2025·Fertility and sterility
To determine whether an association exists between in vitro fertilization (IVF) and severe maternal morbidity among low-risk pregnant patients. Retrospective cohort study. Low-risk pregnant patients who delivered between January 2019 and December 2022. Low-risk was defined as having an obstetric comorbidity index score of 0. In vitro fertilization. MAIN OUTCOME MEASURE(S): The primary outcome (dependent variable) was any severe maternal morbidity. The secondary outcome was the need for a cesarean delivery. A modified Poisson regression with robust error variance was used to model the probability of severe maternal morbidity as a function of IVF. Risk ratios and their associated 95% confidence intervals (CIs) were computed. An α value of 0.05 was considered statistically significant. RESULT(S): A total of 39,668 pregnancies were included for analysis, and 454 (1.1%) were conceived by IVF. The overall severe maternal morbidity rate was 2.4% (n = 949), with the most common indicator being blood transfusion. The overall cesarean delivery rate was 18.8% (n = 7,459). On modified Poisson regression, IVF-conceived pregnancies were associated with 2.56 times the risk of severe maternal morbidity (95% CI, 1.73-3.79) and 1.54 times the risk of having a cesarean delivery (95% CI, 1.37-1.74) compared with non-IVF pregnancies. CONCLUSION(S): In vitro fertilization is associated with higher rates of severe maternal morbidity, primarily the need for a blood transfusion, and cesarean delivery in low-risk pregnancies without major comorbidities. Recognizing this association allows healthcare providers to implement proactive measures for better monitoring and tailored postpartum care.
H Petersen S et al., 2023·Hypertension (Dallas, Tex. : 1979)
Frozen embryo transfer (frozen-ET) is increasingly common because of improved cryopreservation methods and elective freezing of all embryos. Frozen-ET is associated with higher risk of hypertensive disorders in pregnancy than both natural conception and fresh embryo transfer (fresh-ET), but whether this is attributable to parental factors or treatment is unknown. Using the Medical Birth Registries of Denmark (1994-2014), Norway, and Sweden (1988-2015), linked to data from national quality registries and databases on assisted reproduction, we designed a population-based cohort study with within-sibship comparison. We included 4 426 691 naturally conceived, 78 300 fresh-ET, and 18 037 frozen-ET singleton pregnancies, of which 33 209 sibships were conceived using different conception methods. Adjusted odds ratios (aOR) of hypertensive disorders in pregnancy for fresh-ET and frozen-ET versus natural conception with 95% CI were estimated using multilevel logistic regression, where random effects provided conventional population-level estimates and fixed effects gave within-sibship estimates. Main models included adjustment for birth year, maternal age, parity, and country. Risk of hypertensive disorders in pregnancy was higher after frozen-ET compared to natural conception, both at population-level (7.4% versus 4.3%, aOR, 1.74 [95% CI, 1.61-1.89]) and within sibships (aOR, 2.02 [95% CI, 1.72-2.39]). For fresh-ET, risk was similar to natural conception, both at population-level (aOR, 1.02 [95% CI, 0.98-1.07]) and within sibships (aOR, 0.99 [95% CI, 0.89-1.09]). Frozen-ET was associated with substantially higher risk of hypertensive disorders in pregnancy, even after accounting for shared parental factors within sibships.
To determine whether there are any increases in pregnancy-related complications and adverse pregnancy outcomes in singleton pregnancies after assisted reproductive technology (ART) compared with those conceived naturally. Meta-analysis. University-affiliated teaching hospital. PATIENT(S): Singleton pregnancies conceived with ART and naturally. INTERVENTION(S): PubMed, Google Scholar, Cochrane Libraries and Chinese database were searched through March 2015 to identify studies that met pre-stated inclusion criteria. Either a fixed- or a random-effects model was used to calculate the overall combined risk estimates. Subgroup analysis was performed to explore potential heterogeneity moderators. MAIN OUTCOME MEASURE(S): Pregnancy-related complications and adverse pregnancy outcomes. RESULT(S): Fifty cohort studies comprising 161,370 ART and 2,280,241 spontaneously conceived singleton pregnancies were identified. The ART singleton pregnancies had a significantly increased risk of pregnancy-induced hypertension (relative risk [RR] 1.30, 95% confidence interval [CI] 1.04-1.62; I(2) = 79%), gestational diabetes mellitus (RR 1.31, 95% CI 1.13-1.53; I(2) = 6%), placenta previa (RR 3.71, 95% CI 2.67-5.16; I(2) = 72%), placental abruption (RR 1.83, 95% CI 1.49-2.24; I(2) = 22%), antepartum hemorrhage (RR 2.11, 95% CI 1.86-2.38; I(2) = 47%), postpartum hemorrhage (RR 1.29, 95% CI 1.06-1.57; I(2) = 65%), polyhydramnios (RR 1.74, 95% CI 1.24-2.45; I(2) = 0%), oligohydramnios (RR 2.14, 95% CI 1.53-3.01; I(2) = 0%), cesarean sections (RR 1.58, 95% CI 1.48-1.70; I(2) = 92%), preterm birth (RR 1.71, 95% CI 1.59-1.83; I(2)=80%), very preterm birth (RR 2.12, 95% CI 1.73-2.59; I(2) = 90%), low birth weight (RR 1.61, 95% CI 1.49-1.75; I(2) = 80%), very low birth weight (RR 2.12, 95% CI 1.84-2.43; I(2) = 67%), small for gestational age (RR 1.35, 95% CI 1.20-1.52; I(2) = 82%), perinatal mortality (RR 1.64, 95% CI 1.41-1.90; I(2)=45%), and congenital malformation (RR 1.37, 95% CI 1.29-1.45; I(2)=41%). Relevant heterogeneity moderators have been identified by subgroup analysis. Sensitivity analysis yielded consistent results. No evidence of publication bias was observed. CONCLUSION(S): The ART singleton pregnancies are associated with higher risks of adverse obstetric outcomes. Obstetricians should manage these pregnancies as high risk.