Intra-Abdominal Pressure Measurements in Term Pregnancy and Postpartum: An Observational Study

Objective: To determine intra-abdominal pressure (IAP) and to evaluate the reproducibility of IAP-measurements using the Foley Manometer Low Volume (FMLV) in term uncomplicated pregnancies before and after caesarean section (CS), relative to two different reference points and to non-pregnant values. Design: Observational cohort study. Setting: Secondary level referral center for feto-maternal medicine. Population: Term uncomplicated pregnant women as the case-group and non-pregnant patients undergoing a laparoscopic assisted vaginal hysterectomy (LAVH) as control group. Methods: IAP was measured in 23 term pregnant patients, before and after CS and in 27 women immediately after and 1 day after LAVH. The midaxillary line was used as zero-reference (IAP(MAL)) in all patients and in 13 CS and 13 LAVH patients, the symphysis pubis (IAP(SP)) was evaluated as additional zero-reference. Intraobserver correlation (ICC) was calculated for each zero-reference. Paired student's t-tests were performed to compare IAP values and Pearson's correlation was used to assess correlations between IAP and gestational variables. Main outcome measures: ICC before and after surgery, IAP before and after CS, IAP after CS and LAVH. Results: The ICC for IAP(MAL) before CS was lower than after (0.71 versus 0.87). Both mean IAP(MAL) and IAP(SP) were significantly higher before CS than after: 14.0 +/- 2.6 mmHg versus 9.8 +/- 3.0 mmHg (p<0.0001) and 8.2 +/- 2.5 mmHg versus 3.5 +/- 1.9 mmHg (p = 0.010), respectively. After CS, IAP was not different from values measured in the LAVH-group. Conclusion: IAP-measurements using FMLV is reproducible in pregnant women. Before CS, IAP is increased in the range of intra-abdominal hypertension for non-pregnant individuals. IAP significantly decreases to normal values after delivery.