 An uncommon occurrence, but one that is associated with spontaneous preterm   birth (SPTB), pica is harmful to any woman, but presents real danger to a pregnant   woman and her baby by blocking iron absorption and causing severe anemia. Adjusting   for race, alcohol use, and prior SPTB, women with pica are almost twice as likely   to deliver preterm, when compared to those on a normal diet. (OR 1.9, 95% CI   1.1-3.3) For instance, SPTB at less than 37 weeks occurred in 12% of women with   pica, versus 6% in those without. 

 In a study presented at the 2004 ACOG Annual Meeting, Manisha V. Patel, MD,   and associates, from the University of Alabama at Birmingham, observed 3,149   pregnant women at 19 to 26 5/7 weeks' gestation, with an overall pica prevalence   of 4%. 

 Pica was more prevalent in black (5%) than in nonblack women (1%, 

<   0.0001) and more prevalent in women who drank one or more alcoholic drinks per   day as opposed to those who did not. Anemia (hematocrit < 30) was higher   in women with pica (15%) than in those without (6%), (

 Patel MV, Nuthalapaty FS, Ramsey PS et al. Pica: A neglected   risk factor for preterm birth. 