Table 1.
General characteristics and quality scores of the 14 studies included in this meta-analysis
| No | Author, publication year, design (matched variables), study site, country, PW (no, HBsAg +%) , enrolled period (and NOS) | Inclusion/exclusion | Identification of HBsAg/GDM (data retrieval) |
Baseline comparison between HBsAg + and HBsAg- PW |
Effect estimation (95% CI)/adjustment variables | |
|---|---|---|---|---|---|---|
| Similarity | Dissimilarity | |||||
| 1. |
Wong SF, 1999 |
PW delivered after 24 GW or babies with BW ≥ 500 g/AHP, non-SP, acute pelvic inflammatory disease, STI, smoker or illicit drug users, and DM |
ELISA/Australian criteria (computer database) |
Mean age, parity, history of abortion |
NA |
ORc = 1.05 (0.69, 1.61) |
| RCS, with all HBsAg- as controls | ||||||
| ORa = 1.00 (0.56,1.76)*1/NA | ||||||
| Princess Margaret Hospital | ||||||
| Hongkong, China | ||||||
| SP (7105, 11.6%) | ||||||
| Jul.1,1996-Aug.31,1998 (6) | ||||||
| 2. |
Lao TT, 2003 |
Chinese PW, recruited at 28-30 GW, haemoglobin concentration ≥10 g/dl and mean cell volume ≥ 80 fL at the initial visit at or before 14 GW/antenatal visit after 14 GW, anemia or hemoglobinopathy, GDM diagnosed before 28 GW, non-SP |
ELISA/WHO criteria (medical record) |
Weight, height, BMI, parity, socioeconomic status |
The HBsAg + PW were significantly older, with more OGTTs performed, with higher iron status, with higher prevalence of past obstetric history, family or medical history and had an advanced age (≥35 years) |
RRc = 2.97 (2.00, 4.42) |
| RCS, with a sample as controls |
ORc = 3.94 (2.27, 6.84) |
|||||
| Queen Mary Hospital or others |
RRa = 3.51 (1.83, 6.73)/Age, BMI, socioeconomic status, parity and presence of significant obstetrics, family and past history. |
|||||
| Hongkong, China | ||||||
| SP (767, NA) | ||||||
| Over four months (5) | ||||||
| 3. |
To WWK, 2003 |
PW delivered after 24 GW/AHP(2); incomplete or contradicting data(152) |
ELISA/Australian criteria (computer database) |
Age, GW at delivery, BMI, parity, incidence of non-SP or STIs; no clinical manifestations of liver disorders or hepatitis. |
A higher prop. of HBsAg + PW from mainland China |
ORc = 0.81 (0.59, 1.12 ) |
| RCS, with all HBsAg- as controls | ||||||
| ORa = 0.77 (0.47, 1.26)*1/NA | ||||||
| United Christian Hospital | ||||||
| Hongkong, China | ||||||
| AP (13946, 9.72%) | ||||||
| Jan. 1997-Dec. 2000 (6) | ||||||
| 4. |
Tse KY, 2005 |
NA/incomplete data |
ELISA/WHO criteria (medical record) |
BMI, height, weight and Hb level at booking, ethnic, history of stillbirth, IVF pregnancy, haemoglobin level at booking, past medical history |
Among the HBsAg + PW, the weight gain in those with GDM was significant less than those without GDM. |
ORc = 1.89 (1.14, 3.13) |
| RCS, matched for age and parity | ||||||
| ORa = 2.04 (1.21, 3.44)/Age, weight and parity | ||||||
| Queen Mary Hospital (section mainly for high-risk paturients) | ||||||
| Hongkong, China | ||||||
| SP (3348, 7.56%) |
Among the HBsAg- PW, the weight gain in those with GDM was non-significant less than those without GDM. |
|||||
| Jan. 2000-2002 (7) | ||||||
| 5. |
Lao TT, 2007 |
SP, 99% of those PW delivered at or after 24 GW/incomplete data (147) |
ELISA/ WHO criteria*4 (computer database, ICD coding) |
Age, height, parity and history of DM |
The HBsAg + PW had lower weight and BMI, with lower prop. of overweight and smokers, and with higher prop. of Asian origin, married, unemployed and history of induced abortion. |
ORc = 1.31(1.08, 1.57) |
| RCS, with all HBsAg- as controls | ||||||
| ORa = 1.24 (1.01, 1.51)/parity, age, BMI, presence of iron deficiency anaemia, and smoking. | ||||||
| Queen Mary Hospital | ||||||
| Hongkong, China | ||||||
| SP (14464, 8.3%) | ||||||
| 1998-2001 (8) | ||||||
| 6. |
Lert-amornpong S,2007 |
Healthy PW Age 20-39 years old/chronic illness, non-SP, HIV+, smoker, alcohol drinker |
ELISA/NDDG (medical record) |
Age, weight at booking, weight gain, hematocrit at booking, history of contraception, parity and past health. |
NA |
ORc = 3.04 (0.60, 15.28) |
| RCS, matched for age and date of delivery | ||||||
| ORa = 2.89 (0.55, 15.17)*1/NA | ||||||
| Phramongkutklao College of Medicine | ||||||
| Bangkok,Thailand | ||||||
| SP (8515, 1.93%) | ||||||
| Jan.1, 2003-Dec.31,2005 (5) | ||||||
| 7. |
Thungsuk R, 2008 |
Healthy PW |
ELISA/ADA (medical record) |
Age, hematocrit at booking, parity and past health |
NA |
ORc = 1.39 (0.37, 5.28) |
| RCS, matched for age, parity and year of delivery |
Age 20-39 years old/chronic illness, non-SP, HIV+, smoker, alcohol drinker |
|||||
| ORa = 1.32 (0.33, 5.29)*1/NA | ||||||
| Sawanpracharak Hospital | ||||||
| Nakhonsawan, Thailand | ||||||
| AP (2548, 1.3%) | ||||||
| Jan. 2005-Dec, 2007 (5) | ||||||
| 8. |
Saleh-Gargari S, 2009 |
SP/AHP |
ELISA/ADA (medical record) |
Age, parity, BMI, hemoglobin level at admission, past health history |
NA |
ORc = 4.13 (1.96, 8.70) |
| RCS, matched for age, parity, and BMI | ||||||
| ORa = 3.62 (1.60, 7.90)/NA | ||||||
| the labor ward in Mahdieh and Vali Asr Tertiary Care Hospital | ||||||
| Tehran, Iran | ||||||
| SP (NA, NA) | ||||||
| Mar. 2001-Dec. 2008 (6) | ||||||
| 9. |
Aghamohammadi A, 2011 |
SP/ |
ELISA/ADA (medical record) |
Age, parity, haemoglobin level at booking, past medical history |
NA |
ORc = 2.34 (1.32, 4.17) |
| RCS, matched for age and parity, selected at random |
AHP |
ORa = 1.53 (1.19, 1.97)/NA |
||||
| the labor ward in Imam Khomeyni | ||||||
| Sari, Iran | ||||||
| SP (2953, 5.07%) | ||||||
| Jan.,2005-Dec.,2008 (6) | ||||||
| 10. |
Lobstein S, 2011 |
SP (8193)/non-SP (427); HBsAg not available (887) |
ELISA/IADPSG (computer database) |
BMI, age, history of stillbirths, ectopic pregnancies, IVF pregnancies |
The HBsAg + PW had lower weight and height, higher prop. of Asian origin, married, unemployed, history of induced abortion, and lower prop. of primipara |
ORc = 2.82 (0.17, 46.68) |
| RCS, with all HBsAg- as controls | ||||||
| ORa = 2.20 (0.13, 37.03)*1/NA | ||||||
| Gynecological University Hospital | ||||||
| Leipizig, Germany | ||||||
| AP (9507, 0.48%) | ||||||
| Jan 1, 2001-Dec. 31,2006 (6) | ||||||
| 11. |
Reddick KL, 2011 |
NA/DM, HCV |
ELISA/ADA |
NA |
The HBsAg + PW were younger, with more black and Asian, and higher prop. of public-assisted insurance, any substance use, any STI and medical complications |
ORc = 1.78 (1.27, 2.50) |
| RCS, with all HBsAg- as controls | ||||||
| ORa = 1.39 (0.88, 2.12)/age, race, insurance status, substance use, STI and medical complications | ||||||
| 1054 hospitals | ||||||
| 37 states, USA | ||||||
| AP (297664, 0.27%) | ||||||
| 1995–2005 (8) | ||||||
| 12. |
Lu YP, 2012 |
SP/pre-existing diabetes, impaired glucose tolerance, hypertension, etc; syphilis, HIV; co-infected or super-infected with HCV, HDV, HAV, HEV and other infections, smokers drug users, alcohol drinkers and prescription users. |
ELISA/ADA (medical record) |
Age, height, BMI before pregnancy, parity, times of pregnancy, GW |
NA |
ORc = 0.90 (0.48, 1.67) |
| RCS, with a random sample of all HBsAg- as controls | ||||||
| ORa = 0.85 (0.41, 1.77)*1/NA | ||||||
| First Affiliated Hospital of Jinan University | ||||||
| Guangzhou,,China | ||||||
| SP (NA, NA) | ||||||
| May 2009-Jul. 2011 (6) | ||||||
| 13. |
Lao TT, 2013 |
PW delivered at or after 24 GW/NA |
ELISA/Australian criterion (computer database, ICD coding) |
Height and medical history |
The HBsAg + PM were insignificantly younger, and with higher prop. of overweight, BMI and multiple parity |
ORc = 0.96 (0.88, 1.04) |
| RCS, with all HBsAg- as controls |
ORa = 0.91 (0.62, 1.34)*1/NA |
|||||
| Princess of Wales Hospital | ||||||
| Hongkong, China | ||||||
| SP (86537, 10.0%) | ||||||
| Jan. 1995-Dec. 2009 (5) | ||||||
| 14. | Mak SL, 2013 |
PW delivered after 24 GW | ELISA/Australian criterion (computer database) | Maternal condition and past medical health | Parity was higher in HBsAg + PW | ORc = 0.97 (0.74, 1.28) |
| RCS, with all HBsAg- as controls | ||||||
| ORa = 0.92 (0.58, 1.48)*1/NA | ||||||
| Queen Elizabeth Hospital | ||||||
| Hongkong, China | ||||||
| AP (9526, 7.85%) | ||||||
| Oct. 1st, 2010- Dec. 31st, 2011 (6) | ||||||
Notes.
PW: pregnant women; NOS: Newcastle-Ottawa Quality Assessment Scale; no: number; HBsAg: hepatitis B virus surface antigen; GDM: gestational diabetes mellitus; CI: confidence interval; RCS: retrospective cohort study; SP: single pregnancy; GW: gestational weeks; BW: birth weight; AHP: acute hepatitis during pregnancy; STI: sexually transmitted infection; DM: diabetes mellitus; ELISA: Enzyme-linked immunosorbent assay; NA: not available; ORc: crude odds ratio; ORa: adjusted odds ratio; WHO: World Health Organization; BMI: body mass index; OGTT: oral glucose tolerance test; RRc: crude risk ratio; RRa: adjusted risk ratio; Hb: haemoglobin; IVF: In vitro fertilization; prop: proportion; HIV: human immunodeficiency virus; NDDG: National Diabetes Data Group; ADA: American Diabetes Association; IADPSG: International Association of Diabetes in Pregnancy Study Group; HCV: hepatitis C virus; HDV: hepatitis D virus; HAV: hepatitis A virus; HEV: hepatitis E virus; ICD: International Classification of Diseases.
*1ORa was calculated using external estimates of confounding by the method of coefficient adjustment.