Aim: to assess the rate of uterine involution and cavity changes on 3-4-5th day after spontaneous labor and caesarean delivery.
Materials and methods: The ultrasound examination of the uterus was conducted over 558 women in the postpartum period. On the 3rd day after delivery, 177 women were examined, on the 4th day – 299, and on the 5th day – 82. Vaginal delivery occurred in 454 (81.4%) patients, and 104 (18,6%) had caesarean delivery. In all cases there were precipitous labors, with single alive fetus, weighting 2640-4870g. Transabdominal ultrasound examination was conducted by one physician. The uterine volume was calculated by following formula: А∙В∙С∙0,523, where A is the uterine corpus length (cm), B is the anteroposterior diameter (cm), С is the transverse diameter (cm), and 0,532 is the coefficient. Similarly, data of the volume of the uterine cavity was obtained, and endometrial echo complex was analysed. For estimation of the rate of uterine involution and cavity reduction, the ratio of the volume of the cavity to the volume of the uterine body was calculated with the formula: Vcavity: Vuterus ∙ 100%.
Results: The condition of the uterine cavity, which decreases in anteroposterior diameter and volume, has the most important value for the evaluation of the postpartum period. Outrunning contraction of uterine cavity compare to the myometrium demonstrates the ratio of cavity to uterine body volume, which decreases from 8.0 per cent by 3rd day to 4.7 per cent by 5th day. If a hematometra persists, there was no reliable increase in uterine volume. Compare to the norm, the cavity of the uterus is reliably (p<0.05) larger than endometrial echo complex anteroposterior diameter, in the volume and in the ratio of the cavity to the volume of the uterus. Presence of retained placental tissue on the 3-4th day of the puerperium does not lead to subinvolution of the uterus, and also, it has no effect to the endometrial echo complex anteroposterior diameter and the cavity volume (p<0.05). Сaesarean delivery with normal postoperative period, and the presence of a uterine leiomyoma with a diameter less 30 mm, do not increase the volume of the uterus, neither its cavity, if compare to the normal rates.
Conclusion: When assessing the course of the postpartum period for 3-5 days, the state and size of the cavity should be given more importance than the uterus; the uterine volume is subject to pronounced individual fluctuations.