Effect of coffee consumption on fetal renal artery blood flow and amniotic fluid volume in third trimester of pregnancy

OBJECTIVE: Coffee is frequently (one or two cups/day) consumed throughout pregnancy. Although there are a few studies evaluating caffeine effects on pregnancy; however, a diuretic effect of caffeine on fetal kidneys has not been reported. Therefore, after drinking coffee whether changing of amniotic fluid index (AFI) and fetal renal artery blood flow (FRABF, RI, Resistive index; PI, Pulsatility index) were evaluated in this study. METHODS: This clinical study was performed with two groups. For the study group, 63 participants with isolated borderline oligohydramnios who agreed to drink one cup of instant coffee were included in this study while 63 participants with isolated borderline oligohydramnios who did not drink one cup of instant coffee formed the control group. AFI, RI and PI were evaluated both before and after coffee intake. RESULTS: Maternal characteristics of all study population were homogenous. FRABF indices were similar in both before and after coffee consumption. AFI was increased significantly six hours after drinking coffee (p<0.001). CONCLUSIONS: The coffee consumption increased the amniotic fluid volume. However it does not seem to affect on FRABF. According to our study findings, coffee consumption may offer a new opportunity to improve amniotic fluid volume for pregnant women with oligohydramnios.