DESIGN: A quasi-experimental study comparing 2 groups: (1) integrated maternal health care (MHC) program (with preconception care) and (2) standard MHC program (without preconception care).

SETTING: Maternal health-care clinics in Alvand and Qazvin cities in Qazvin Province, Iran.

PARTICIPANTS: A total of 152 and 247 Iranian women aged 16 to 35 years were enrolled in the integrated MHC and standard MHC program, respectively.

MEASURES: The birth outcomes measured included low birth weight, preterm birth, maternal and neonatal complications, and mode of delivery (normal vaginal delivery and cesarean delivery).

ANALYSIS: Multiple logistic regression was performed to determine the impact of preconception care and risk of adverse birth outcomes with adjusted odds ratios (ORs) as effect sizes.

RESULTS: One hundred forty-seven women in integrated MHC and 218 women in standard MHC completed this study. Preconception care was associated with reduced risk of preterm birth (OR = 0.298; 95% confidence interval [CI] = 0.120-0.743; P = .009), low birth weight (OR = 0.406; 95% CI = 0.169-0.971; P = .043), maternal complication (OR = 0.399; 95% CI = 0.241-0.663; P < .001), and neonatal complications (OR = 0.460; 95% CI = 0.275-0.771; P = .003).