Online Supplemental Material
Online Supplemental Material
Online Supplemental Table 1. Detailed list of conditions included in each cause of fetal death category.
Category / Conditions includedMaternal medical conditions during pregnancy / Hypertensive disorder of pregnancy
Diabetes during pregnancy
Systemic lupus erythematosus
Intrahepatic cholestasis of pregnancy
Thyroid disorders during pregnancy
Renal disease during pregnancy
Shock during pregnancy
Asthma during Pregnancy
Seizure disorders during pregnancy
Maternal substance abuse
Heritable thrombophilias
Antiphospholipid syndrome
Other maternal medical condition
Obstetric complications / Fetal maternal hemorrhage
Cervical insufficiency with antepartum death
Preterm labor with antepartum death
Preterm premature rupture of membranes with antepartum death
Intrapartum fetal death with labor ≤26 weeks’ gestation
Hypoxic intrapartum fetal death >26 weeks’ gestation
Uterine rupture
Maternal trauma during pregnancy
Uteroplacental insufficiency
Other obstetric complications
Fetal genetic, structural, and karyotypic abnormalities / Chromosomal anomalies
Autosomal recessive disorders
X-linked dominant disorders in males
Structural anomalies without chromosomal anomaly
Fetal metabolic disorders
Placental membrane pathology - early amnion rupture sequence
Compromise of maternal/fetal circulation - placental and/or fetal hydrops
Other chromosomal, genetic or structural abnormalities
(Continued)
Online Supplemental Table 1. Continued
Category / Conditions includedPlacental disease / Implantation site abnormalities (e.g., placenta previa)
Abnormal development of villous parenchyma (e.g., delayed maturation, accelerated maturation)
Circumvallate, velamentous, or furcated cord insertion with compromise
Amnion nodosa
Chronic villitis
Chorangiosis
Compromised maternal circulation – vascular and nonvascular lesions
Fetal thromboembolism
Uteroplacental insufficiency
Other placental abnormalities
Umbilical cord abnormalities / Cord entrapment
Knots, torsions, strictures
Cord prolapse
Vasa previa
Umbilical vein rupture
Maternal, placental and/or fetal infection / Severe maternal infection
Fetal infection involving vital organs
Fetal infection causing congenital anomaly or other fetal condition
Placental infection likely leading to decreased placental function
Clinical chorioamnionitis with antepartum death
Histologic chorioamnionitis
Infection-related fetal death by other or unknown mechanisms
Abruption / Abruptio placentae
Other / Platelet alloimmunization
Red cell isoimmunization
Other maternal or fetal hematologic conditions
Online Supplemental Material
Online Supplemental Table 2. Frequency of stillbirth by probable cause, presence of labor, and timing in gestation.
Alln(%) / Timing of stillbirth / Gestational age (weeks)
Antepartum
n(%) / Intrapartum
n(%) / 16-19
n(%) / 20-27
n(%) / 28-36
n(%) / ≥37
n(%)
Probable cause of death
Placental abruption / 145 (22) / 83 (16) / 62 (43) / 51 (22) / 46 (23) / 44 (32) / 4 (5.1)
Placental disease / 124 (19) / 112 (22) / 12 (8.3) / 17 (7.2) / 48 (24) / 43 (31) / 16 (20)
Obstetric complications / 146 (22) / 14 (2.7) / 132 (91) / 73 (31) / 58 (29) / 9 (6.5) / 6 (7.6)
Infection / 111 (17) / 73 (14) / 38 (26) / 53 (22) / 36 (18) / 13 (9.4) / 9 (11)
Maternal medical complications / 78 (12) / 74 (14) / 4 (2.8) / 9 (3.8) / 21 (10) / 41 (30) / 7 (8.9)
Fetal genetic structural abnormalities / 84 (13) / 74 (14) / 10 (6.9) / 29 (12) / 27 (13) / 18 (13) / 10 (13)
Umbilical cord abnormalities / 50 (7.6) / 40 (7.8) / 10 (6.9) / 7 (3.0) / 15 (7.4) / 11 (7.9) / 17 (22)
Other / 10 (1.5) / 8 (1.6) / 2 (1.4) / 1 (0.4) / 6 (3.0) / 2 (1.4) / 1 (1.3)
Any probable cause / 483 (73) / 338 (66) / 145 (100) / 150 (63) / 164 (80) / 118 (84) / 56 (70)
Total / 658 (100) / 513(100) / 145(100) / 237(100) / 203(100) / 139(100) / 79(100)
Online Supplemental Table 3. Association between maternal prepregnancy body mass index category and stillbirth limited to observations with complete data (n=400 cases), to stillbirths at ≥20 weeks (n=421 cases), or to patients receiving antenatal care at our hospital (n=496 cases).
Restriction / Prepregnancy BMI category / Adjusted1 HR (95% CI)Patients with complete data
Lean / 1.0 (ref)
Overweight / 1.5 (1.2, 2.0)
Obese / 1.7 (1.1, 2.4)
Severely obese / 1.8 (1.2, 2.7)
Stillbirths at ≥20 weeks
Lean / 1.0 (ref)
Overweight / 1.4 (1.0, 1.8)
Obese / 1.7 (1.2, 2.5)
Severely obese / 1.6 (1.1, 2.4)
Patients receiving antenatal care at our hospital
Lean / 1.0 (ref)
Overweight / 1.5 (1.2, 2.0)
Obese / 1.8 (1.3, 2.5)
Severely obese / 2.1 (1.5, 3.0)
BMI, body mass index; CI, confidence interval; HR, hazard ratio
Lean, BMI <25 kg/m2; overweight, BMI 25-<30 kg/m2; obese, BMI 30-<35 kg/m2; severely obese, BMI ≥35 kg/m2.
1Adjusted for maternal race/ethnicity, maternal age, maternal education, parity, smoking during pregnancy, marital status, and trimester of entry to prenatal care.
Online Supplemental Table 4. Association between maternal prepregnancy body mass index category and stillbirth defined by probable and possible cause.
Cause of stillbirth / Prepregnancy BMI category / Number of cases / Unadjusted HR (95% CI) / Adjusted1 HR (95% CI)Aneuploidy
Lean / 24 / 1.0 (ref) / 1.0 (ref)
Overweight / 8 / 1.1 (0.5, 2.5) / 1.2 (0.5, 2.6)
Obese / 10 / 2.2 (1.0, 5.1) / 2.3 (1.0, 5.5)
Severely obese / 6 / 2.1 (0.8, 5.2) / 2.2 (0.8, 5.8)
Fetal thromboembolism
Lean / 23 / 1.0 (ref) / 1.0 (ref)
Overweight / 13 / 1.2 (0.6, 2.5) / 1.2 (0.6, 2.6)
Obese / 9 / 2.5 (1.1, 5.6) / 2.5 (1.1, 5.7)
Severely obese / 6 / 1.9 (0.7, 4.9) / 1.8 (0.7, 4.7)
Parenchymal infarcts
Lean / 24 / 1.0 (ref) / 1.0 (ref)
Overweight / 14 / 1.6 (0.8, 3.2) / 1.8 (0.9, 3.7)
Obese / 10 / 2.3 (1.0 , 5.1) / 2.3 (1.0, 5.4)
Severely obese / 12 / 3.1 (1.5, 6.6) / 2.8 (1.2, 6.6)
Hypertensive disorder
Lean / 22 / 1.0 (ref) / 1.0 (ref)
Overweight / 25 / 2.5 (1.4, 4.7) / 2.6 (1.4, 4.9)
Obese / 14 / 3.4 (1.6, 6.8) / 3.1 (1.5, 6.5)
Severely obese / 14 / 4.2 (2.1, 8.5) / 3.6 (1.7, 7.7)
Fetal membranes and placental inflammatory disorders with antepartum death
Lean / 29 / 1.0 (ref) / 1.0 (ref)
Overweight / 19 / 1.4 (0.7, 2.6) / 1.3 (0.7, 2.5)
Obese / 9 / 1.8 (0.8, 4.1) / 1.6 (0.7, 3.8)
Severely obese / 6 / 1.3 (0.5, 3.6) / 0.9 (0.3, 2.6)
Fetal infection involving vital organs and antepartum death
Lean / 25 / 1.0 (ref) / 1.0 (ref)
Overweight / 18 / 1.4 (0.7, 2.8) / 1.3 (0.7, 2.6)
Obese / 11 / 2.1 (0.9, 4.8) / 1.9 (0.8, 4.5)
Severely obese / 4 / 1.1 (0.4, 3.4) / 0.8 (0.3, 2.6)
Lean, BMI <25 kg/m2; overweight, BMI 25-<30 kg/m2; obese, BMI 30-<35 kg/m2; severely obese, BMI ≥35 kg/m2.
1Adjusted for maternal race/ethnicity, maternal age, maternal education, parity, smoking during pregnancy, marital status, and trimester of entry to prenatal care.
CI, confidence interval; HR, hazard ratio