Study characteristics
The year of publication of the included trials ranged between 1998 and
2020, spanning 22 years. Twelve trials included only nulliparous women,
2 trials included only multiparous women, 4 trial included both
nulliparous and multiparous women, one trials didn’t report the parity.
Participants were full-term pregnant women (gestational age≥37 weeks).
Four Lubricants classes were evaluated, including obstetric gel (n=8),
liquid wax (n=9), liquid petroleum jelly (n=1), and peanut oil (n=1).
The number of participants ranged from 62 to 800 (Table S1).