TABLE 2.

Risk of bias

	Bias Domains
Author (year)	Selection	Performance	Detection	Attrition	Reporting	Other	Authors’ Judgement of Risk of Bias	Support
McGowan et al. (1999) (38)	+	+	+	−	+	+	High	Small, nonrandomized observational sample without a comparison group available for analysis. Did not control for confounders.
Wimalasundera et al. (2002) (3)	+	+	+	−	−	+	High	Case-control study with small sample sizes and multiple subgroup analyses. Matched HIV-negative control group for age, parity, and ethnic origin.
Mattar et al. (2004) (37)	+	+	+	−	−	+	High	Small, nonrandomized, single-site retrospective cohort. Controls were only matched based on HIV status. Authors reported limited baseline demographics with no comparisons between HIV-positive and HIV-negative groups.
Tuomala et al. (2005)(47)	+	+	+	−	+	+	High	Large, multicenter, prospective cohort analysis. HDP outcomes are not reported in their entirety and confounders were not controlled.
Bodkin, Klopper, & Langley (2006) (22)	+	+	+	−	+	+	Moderate	Single-site retrospective cohort analysis which reported selective HDP outcomes (e.g. eclampsia and pregnancy-induced hypertension). Random sampling was employed to generate HIV- positive cohort with matched controls in a 1:2 fashion for HIV status. Analysis did not control for confounding variables.
Kourtis et al. (2006) (24)	+	−	+	−	+	−	Moderate	Large retrospective cohort analysis. Significant baseline differences among individuals with HIV and without. Detection of hospitalization based on ICD-9 coding. Does not document medical history of the cohort, which may have an impact on development of HDP.
Suy et al. (2006) (32)	+	+	+	−	+	+	Moderate	Prospective, single-site, non-randomized cohort analysis. One outcome focused on preeclampsia and did not discuss other HDPs. For matched controls, historical in nature and based on HIV status, rather than HIV status and cART exposure. Analysis only controlled for a few confounding variables.
Boer et al. (2007) (28)	+	+	+		+	+	Moderate	Retrospective, nonrandomized cohort analysis. Offered matched, HIV-negative controls in 1:2 ratio, but did not discuss nonmatched baseline characteristic differences between groups.
Bera (2009) (29)	+	+	−	+	+	+	High	Single center, nonrandomized descriptive study. Did not provide any comparison group for analysis or control for confounders.
Haeri et al. (2009) (7)	+	+	−	+	−	+	Moderate	Retrospective, nonrandomized, observational cohort. Provided matched control group in 1:2 fashion based on multiple baseline characteristics, but unmatched characteristics demonstrated significant differences between groups. Performed multiple comparisons.
Williams et al. (2009) (39)	+	+	+	−	+	+	High	Retrospective, nonrandomized case series of a specific population (e.g. women with perinatally-acquired HIV). Small sample size, with only 3 pregnancies complicated by preeclampsia. Did not describe severity of preeclampsia or timing of onset. No comparison group available for analysis.
Aebi-Popp et al. (2010)(48)	+	+	+	−	+	+	High	Prospective, nonrandomized, observational descriptive study with no comparison group available for analysis. Did not discuss any risk factors associated with preeclampsia.
Parekh et al. (2011) (33)	+	+	+	−	−	+	Moderate	Retrospective, nonrandomized cohort analysis. Did not discuss adherence to cART or use of PI. Hypertension during pregnancy was a secondary outcome.
Boyajian et al. (2012) (8)	−	+	+	−	−	+	Moderate	Single-site, retrospective cohort analysis. Excluded HIV-positive women not using cART. Randomly assigned matched controls in 1:3 ratio. Did not report on other HDP outcomes.
Shapiro et al. (2012) (36)	+	+	+	−	+	+	High	Prospective, nonrandomized, case-control study. Did not control for confounding variables. Small sample size. Did not report medical risk factors for HDP. Dataset focuses on women with stillbirth.
Ngene et al. (2013)(30)	+	+	+	−	+	+	High	Prospective, nonrandomized, single-site cohort analysis. Small sample size with no multivariate analysis performed. Population focused on pregnant or postpartum women admitted to ICU, rather than all admissions. No definition provided for preeclampsia.
Powis et al. (2013) (34)	+	+	+		+	+	High	Secondary analysis of a randomized controlled trial. Noted baseline differences between women who developed preeclampsia and those who did not. However, no discussion of cART adherence. Small number of women who developed preeclampsia.
Hall et al (2014) (9)	+	+	+	+	−	+	High	Prospective, nonrandomized, cohort analysis. Excluded women with risk factors for preeclampsia. Significant baseline differences between HIV-positive and negative women. Did not perform matching for the control group. 1/3 of women enrolled in study did not delivery at study site, and no data is available for them.
Landi et al. (2014) (21)	+	+	+	−	−	+	High	Prospective, nonrandomized, observational cohort analysis. Provided HIV-negative matched cohort for age and parity, while excluding women with medical risk factors for HDP. Did not control for confounders. Did not define criteria for either gestational hypertension or preeclampsia.
Machado et al. (2014) (25)	+	+	+	+	−	+	High	Prospective, nonrandomized, observational cohort analysis of two ongoing studies. Did not provide HIV-negative or HIV-positive cART-unexposed controls for comparison. Small number of women who developed HDP. 35 women were excluded from primary analysis and no data were provided on these subjects.
Reitter et al. (2014)(49)	+	+	+	+	−	+	High	Prospective, nonrandomized, cohort study. No comparison group provided. Did not control for several confounders. Low number of women who developed HDP.
Ewing et al. (2016)(26)	+	+	+	−	−	+	High	Large retrospective, cross-sectional cohort study. Authors did not report baseline co-morbidities which could predispose to HDP. Study relied on ICD-9 codes to make diagnosis.
Maharaj, Moodley, & Chuturgoon (2016) (31)	+	+	+	+	−	+	Moderate	Prospective, observational, nonrandomized cohort study. Study focused only on preeclampsia and did not include gestational hypertension or HELLP.
Sansone et al. (2016)(15)	+	+	+	−	−	+	Moderate	Retrospective, observational, nonrandomized cohort analysis. Unable to discuss adherence or type of cART regimen.
Stoner et al. (2016) (27)	+	+	+		+	+	High	Large number of individuals excluded either due to diagnosis of chronic hypertension, missing information about HDP, or lack of a reported due date. Reporting on HDP was limited due to laboratory access.
Tooke et al. (2016) (23)	+	+	+	−	+	+	High	Single site, nonrandomized, case-control study. Inclusion criteria focused on women delivering extremely low birthweight neonates. Performed multiple comparisons. Did not control for confounding variables.
Yudin et al. (2016) (50)	+	+	+	−	+	+	High	Single site, retrospective, nonrandomized cohort analysis. Small of women who developed HDP. No matched cohort presented for analysis.
Sebitloane, Moodley, & Sartorius (2017) (35)	+	+	+	−	+	+	High	Nonrandomized, case-control study. Data is focused on maternal deaths and does not include baseline characteristics of the subjects in the sample. No regression modeling was performed.