Vaginal discharge changes during pregnancy

By trimester

Weeks 1–13

1st trimester

A steady, mild, odorless increase in discharge is expected as estrogen rises, and discharge is sometimes one of the earliest signs of pregnancy itself. A change in color, odor, or itching still points to the same infections common at any stage, not something unique to early pregnancy.

Weeks 14–27

2nd trimester

Discharge typically keeps increasing through the second trimester as estrogen keeps climbing. This is a common point for a bacterial vaginosis or yeast infection to develop, so a shift to gray, yellow-green, or curd-like discharge with odor or itching is worth a call rather than something to wait out.

Weeks 28–birth

3rd trimester

Discharge often increases further in the third trimester and can include thin mucus streaks near term. From 20 weeks on, any leaking fluid, a watery gush, or a notable discharge change is one of the recognized preterm labor warning signs, which calls for a same-day check rather than a wait-and-see approach.

What does the evidence show for vaginal discharge changes?

• Normal pregnancy discharge is typically thin, clear to milky white, and has only a mild odor, and both the amount and thickness of it increase as estrogen rises, especially by the third trimester. 1
• In one study, pathological discharge, described as yellowish to greenish, curd-like, foul-smelling, or heavy enough to soak clothing, was linked to a higher chance of preterm delivery, premature rupture of membranes, miscarriage, and postpartum infection. 1
• The three most common infections behind abnormal discharge each have a distinct pattern: bacterial vaginosis brings a thin gray discharge with a fishy odor, a yeast infection brings a thick white curd-like discharge that usually isn't foul-smelling but can itch, and trichomoniasis brings a yellow-green, frothy, foul-smelling discharge. 2
• A watery gush or a lighter, continuous leak of fluid can signal that the amniotic membranes have ruptured, since amniotic fluid runs less acidic than normal vaginal secretions. This differs from an ordinary increase in discharge and calls for prompt evaluation. 3
• NICHD lists a change in vaginal discharge, including leaking fluid or bleeding, among the warning signs of preterm labor between 20 and 36 weeks of pregnancy, alongside frequent contractions, pelvic pressure, and a low, dull backache. 4

When should I call my provider about vaginal discharge changes?

A shift to yellow, green, or gray discharge, a curd-like texture, a strong or fishy odor, or new itching and burning points toward an infection like bacterial vaginosis, a yeast infection, or trichomoniasis rather than ordinary pregnancy discharge, and is worth a call regardless of trimester. A watery gush or a steady, light trickle of fluid can mean the amniotic membranes have ruptured and needs same-day evaluation, since it differs from a normal increase in mucus-like discharge. Between 20 and 36 weeks, NICHD lists any notable change in discharge, including leaking fluid or spotting, as one of the recognized warning signs of preterm labor, alongside frequent contractions, pelvic pressure, or a low dull backache, so this window calls for a lower threshold to check in than discharge changes later at full term. When in doubt, call your obstetric team the same day. Early input almost always beats waiting, and the on-call line exists exactly for this.