Open AccessUtero‐Vaginal Differential Pressure During the First Stage of Labour
Author(s) -
Westin Björn,
Söderberg Göran
Publication year - 1971
Publication title -
acta obstetricia et gynecologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 102
eISSN - 1600-0412
pISSN - 0001-6349
DOI - 10.3109/00016347109157314
Subject(s) - medicine , concomitant , in utero , uterine contraction , blood pressure , pregnancy , obstetrics , uterus , vagina , gynecology , fetus , surgery , biology , genetics
Intra‐abdominal (vesical), intra‐uterine and intra‐vaginal pressures were measured in 12 healthy women early in the first stage of labour. Ten subjects were primigravidae and two gravidae‐2. Seven subjects exhibited no significant change of intraabdominal or intra‐vaginal pressures during uterine contractions. Five subjects (4 primigravidae) exhibited no significant change of intra‐abdominal pressure but a large and significant increase of intra‐vaginal pressure concomitant with uterine contractions. In spite of having higher intrauterine peak pressures during contractions, these subjects exhibited significantly smaller expulsive uterine pressures than the former group because of high vaginal counterpressures. It is believed that increased tension of pelvic floor muscles contributes to the elevated vaginal pressure during contraction. Our findings may offer a better understanding of why pain relief in selected patients will aid in accelerating labour and make the birth process less hazardous for the fetus.