Table 3 Impact of birth spacing on stillbirth and perinatal mortality

DaVanzo et al. 2007 [24]

Bangladesh (Matlab). Population-based study, the Matenal Child Health-Family Planning area.

Observational study. Pregnancy outcomes (N = 66,759) that occurred between 1982 and 2002.

Compared the impact of IPIs, beginning with a live birth, of < 6 months in duration vs. 27-to 50-month.

SBR: OR = 1.6 (95% CI: 1.2–2.1).

Induced abortion: OR = 7.5 (95% CI: 6.0–9.4).

Miscarriage: OR = 3.3 (95% CI: 2.8–3.9).

All three types of non-live-birth (NLB) outcomes: increased odds at IPIs > or = 75, but not as risky as very short intervals. IPIs that began with a NLB were generally more likely to end with the same type of NLB

Orji et al. 2004 [27]

Nigeria. University Teaching Hospital Complex.

Comparative matched case-control study. N = 100 multiparae (N = 50 cases, N = 50 controls).

Compared the impact of prolonged birth spacing (> or = 6 years) (cases) vs. shorter birth spacing (2 – 5 years) (controls).

PMR or maternal deaths: None in both groups.

No significant difference in spontaneous onset of labour, induction or argumentation of labour, duration of labour, spontaneous vaginal delivery rates, Caesarean section rates, instrumental vaginal deliveries, analgesic requirement, postpartum hemorrhage, and Apgar scores in both groups.

Smith et al. 2003 [18]

UK (Scotland).

Retrospective cohort study. N = 89,143 women having second births in 1992–8 who conceived within five years of their first birth (N = 69,055 had a first term live birth).

Assessed the association between preceding IPI and the outcome of the second birth in women with a first term live birth after adjusting for different variables.

SBR or IUGR: No significant association.

A short IPI (< 6 months) was an independent risk factor for extremely pre-term birth (adjusted odds ratio 2.2, 1.3 to 3.6), moderately pre-term birth (1.6, 1.3 to 2.0), and neonatal death unrelated to congenital abnormality (3.6, 1.2 to 10.7).

Women whose subsequent IPI was less than six months were more likely than other women to have had a first birth complicated by perinatal death (OR = 24.4, 95% CI: 18.9 to 31.5).

Stephansson et al. 2003 [25]

Sweden. Nationwide study.

Retrospective evaluation of a national cohort.

N = 410,021 women's first and second singleton deliveries between 1983 and 1997.

Compared the impact on pregnancy outcomes of IPIs of short duration (0–3 months) vs. intervals between 12 and 35 months.

SBR: OR = 1.9 (95% CI: 1.3–2.7).

Adj. OR = 1.3 (95% CI: 0.8–2.1).

Early neonatal death: OR = 1.8 (95% CI: 1.2–2.8).

Adj. OR = 0.9 (95% CI: 0.5–1.6).

SBR among women with IPIs of 72 months and longer: adjusted OR = 1.5 (95% CI: 1.1 – 2.1).

Early neonatal death among women with IPIs of 72 months and longer: adjusted OR = 1.3 (95% CI: 0.9 – 2.1).

Abebe and Yohannis 1996 [28]

Ethiopia. Maternity ward at Jimma Hospital.

Cross-sectional study. Women (N = 415) who delivered during September 1992 to March 1993. Three trained midwives collected the information by use of pre-tested questionnaire.

Midwives interviewed mothers regarding age, marital status, income, education, parity, contraceptive usage, duration of breast feeding, and pregnancy outcomes.

Spontaneous abortion: 32.2% vs. 13.2% in intervals under 12 months vs. 12–24 month intervals, respectively.

SBR: 3.2% among birth intervals under 12 months.

Early neonatal death rate (within first week of life): 6.9% among birth intervals under 12 months.

Pregnancy wastage (abortion, stillbirth or neonatal mortality): 42.3% among women with birth intervals under 12 months. The proportion of pregnancy wastage declined with an increased birth interval.

Kallan 1992 [26]

US. Data from the national survey of family growth in 1988.

Retrospective study. N = 104 pregnancies among non-institutionalised women aged 15–44.

Assessed the association of short and long IPIs on IUGR, LBW and fetal loss.

Short and long IPIs increase the risk of both intrauterine growth retardation low birth weight and fetal loss.

Zimmer 1979 [23]

Scotland (Aberdeen).

Observational study.

N = 3098 once married women, who had a pregnancy outcome during the period 1950 to 1955 for a total of 10,825 pregnancies.

Assessed the impact of the spacing of pregnancies on outcome.

Women who experience a wastage at any given pregnancy number are not only more likely to have another pregnancy, but they do so over a short time interval than those whose last pregnancy resulted in a live birth. Except for terminations, wastage is highest among women who closely space their pregnancy.

Kamau and Mati 1988 [122]

Kenya (Nairobi). Kenyatta National Hospital.

Cross sectional survey.

Women (N = 615) delivered during the months of June and July 1985, who had at least one birth interval to report (N = 2407 pregnancies and 1792 birth intervals).

Assessed the impact of birth intervals on pregnancy outcome.

SBR and first week death rates: the lowest rates (1.9% and 3.2% respectively) were observed when the preceding birth interval was 25–36 months. PMR: 5.2% for this interval.

Birth intervals that were 25–36 months long were associated with the most favorable pregnancy outcome. Poor pregnancy outcome was followed by very short birth intervals.