Additional file 1: Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. A list of 27 items required under the PRISMA statement with their respective locations. Additional file 2.: Search strategy for the systematic review and meta-analysis. Complete Search Strategy for a) Embase (1947 to 2020 April 08) b) Ovid MEDLINE, MEDLINE Daily and Epub Ahead of Print, In-Process & Other Non-Indexed Citations (1947 to 2020 April 08) c) EBM Reviews - Cochrane Central Register of Controlled Trials (1947 to April 2020). Additional file 3.: Excluded full text studies, with reasons. A list of full text studies excluded after screening with reasons for removal. Additional file 4.: Newcastle-Ottawa Scale for quality assessment and publication bias. A breakdown of NOS scores assigned to each study included in the meta-analysis. Additional file 5.: Forest plots for preeclampsia and funnel plots. Forest plots comparing preeclampsia in IVF/ICSI pregnancies and spontaneous pregnancies and funnel plots for publication bias in meta-analyses with 10 or more studies. Additional file 6.: Sensitivity analysis. A list of highest and lowest overall odds ratios after removing individual studies.Background: 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.