Birth outcomes
Prematurity
All included trials involving 4845 participants reported the
prematurity, with 2363 pregnant women
were
randomized assigned to receive DP, 2482 were randomized assigned to
receive SP 13,
14, 22-24. The occurrence of prematurity did not differ significantly between the
DP and SP groups (RR=1.02; 95%CI, 0.87–1.19; P = 0.83; I²=0.00%;
Figure S1; see Supplementary Material). Figure 4-A showed that the
occurrence of prematurity did not differ significantly between the
IPT-DP-4-6w and IPT-SP-4-6w,
IPT-DP-8w and IPT-SP-8w groups(RR=1.00; 95%CI, 0.70–1.41; P = 0.98;
I²=10.20%; Figure 4-A). Figure 4-B showed no significant differences
were obtained for prematurity between IST-DP with
IPT-SP-4-6w (RR=1.06; 95%CI,
0.89–1.27; P = 0.51; I²=4.50%; Figure 4-B).
Low birth weight
Figure B showed that five articles, with a total of 4644 participants,
reported the incidence of low birth weight13,
14,
22-24. 2267 randomly assigned to DP
group, 2377 randomly assigned to SP group. DP has similar effect
compared with SP(RR=1.06; 95%CI, 0.88–1.29; P = 0.524; I²=19.2%;
Figure S2). The subgroup analysis indicated similar rates of low birth
weight were noted between different intervals of SP and DP(RR=1.00;
95%CI, 0.73–1.38; P = 0.99; I²=0.00%; Figure 5-A). We noted that
IST-DP, compared with IPT-SP-4-6w, presented similar rates (RR=1.24;
95%CI, 0.96–1.61; P = 0.10; I²=0.00%; Figure 5-B).
Overall mortality (stillbirth and spontaneous abortion)
Four trials reported the effect of DP and SP on stillbirth (RR=0.66;
95%CI, 0.42–1.05; P = 0.09; I²=33.20%;Figure S3; see Supplementary
Material) and three trials reported the incidence of small for
gestational age (RR=0.38; 95%CI, 0.03–5.35; P = 0.34; I²=75.60%;
FigureS4; see Supplementary Material). The subgroup analysis showed
different intervals and regimens of DP were not associated with a better
effect of SP (Figure 6-A, Figure 6-B and Figure 7).
Small for gestational age
The incidence of small for gestational age was evaluated in three
trials, including 4242 participants, and non-significant reduction was
found between DP and SP groups(RR=1.12; 95%CI, 0.91–1.37; P = 0.293;
I²=0%; Figure S5; see Supplementary Material). Figure 8 showed
IPT-DP-4-6w has similar effects to IPT-SP-4-6w(RR=0.99; 95%CI,
0.72–1.37; P = 0.63; I²=0.00%; Figure 8-A)and IST-DP had similar
effects to IPT-SP-4-6w (RR=1.22; 95%CI, 0.96–1.56; P = 0.11;
I²=0.00%; Figure 8-B)