Table 2.

Comparison of APrON and AOB selection criteria

Selection criteria	APrON	AOB-OC	AOB-PC
Maternal age	≥16 years	≥18 years	≥18 years
Language	Able to complete questionnaires in English	Able to complete questionnaires in English	Able to complete questionnaires in English
Gestational age at enrollment	<27 weeks	<24 wks	<17wks
Specific criteria	Not planning to move out of the city within 6 months of inclusion into study	Receiving prenatal care	Nulliparous or primiparous OR personal or familial history of preterm birth;
			Receiving prenatal care;
			Singleton pregnancy