Table 2.

Psychological interventions vs care-as-usual control groups for preventing distress among pregnant women: effect sizes^a

	N comp	d	95% CI	p-value	I2	NNT
All studies	14	0.52	0.29 ~ 0.74		76.14*	3.50
2 outliers removed	12	0.47	0.31 ~ 0.62		26.56 ns	3.85
Lowest ES excludedb	12	0.50	0.36 ~ 0.64		14.9 ns	3.62
Highest ES excludedb	12	0.43	0.25 ~ 0.61		41.54 ns	4.20
Depression onlyb	10	0.50	0.32 ~ 0.67		26.99 ns	3.62
Anxiety onlyb	5	0.30	< 0.01 ~ 0.59		43.03 ns	5.95
Stress onlyb	5	0.52	0.28 ~ 0.75		00.00 ns	3.50
Timing interventionb				0.63
• Prenatal	9	0.52	0.36 ~ 0.68		07.32 ns	3.50
• Mixed	3	0.37	0.16 ~ 0.58		60.95 ns	4.85
Intervention typeb				0.54
• Psychoeducation	3	0.34	0.03 ~ 0.65		22.77 ns	5.26
• CBT	3	0.43	0.24 ~ 0.62		66.23 ns	4.20
• Mindfulness	3	0.32	−.14 ~ 0.78		0.00 ns	5.56
• Other	3	0.62	0.39 ~ 0.84		43.81 ns	2.96
Delivery modeb				0.54
• Group	10	0.45	0.32 ~ 0.58		34.52 ns	4.00
• Individual	2	0.61	0.13 ~ 1.10		00.00 ns	2.99
Inclusion of partnerb				< 0.01
• No	8	0.59	0.43 ~ 0.75		0.00 ns	3.09
• Yes	4	0.25	0.04 ~ 0.45		0.00 ns	7.14
Risk of biasb				0.40
• High	5	0.55	0.32 ~ 0.78		38.08 ns	3.31
• Low	2	0.56	0.32 ~ 0.81		00.00 ns	3.25
• Medium	5	0.35	0.16 ~ 0.54		26.78 ns	5.10
Timing post-testb				0.93
• Pregnancy	5	0.48	0.30 ~ 0.67		0.00 ns	3.76
• 0–6 m pp	7	0.45	0.27 ~ 0.62		51.54 ns	4.00

^a random effect models; ^b analysis did not include four outliers (Khorsandi; Haga); N _comp number of comparisons; ns: not statistically significant; NNT Numbers Needed to Treat