METHODS
This prospective study was conducted in the Department of Obstetrics and
Gynecology of Casilino Hospital in Rome, University of Tor Vergata.
During the period between September 2016 and December 2017, we enrolled
395 patients not in labor.
We used strict inclusion and exclusion criteria. The inclusion criteria
were:
- singleton pregnancy,
- certain dating of pregnancy by I trimester ultrasound using crown-rump
length (CRL),
- gestational age >37+0,
- estimated fetal birth weight >10th centile,
- absence of fetal and maternal disease at enrollment.
Pregnant women were excluded if a maternal or fetal disease was present
(diabetes, hypertensive disorders, IUGR, fetal malformation, etc.), if
the pregnancy was the result of assisted reproduction therapy or if an
elective C-section due to maternal request or breech presentation was
scheduled.
Once the consensus was obtained, the anamnestic, anthropometric and
demographic information were gathered. For each patient, the following
parameters were collected: maternal age, height, weight, BMI, last
menstrual period, gestational age corrected by first trimester
ultrasound, obstetrical history and smoking.
An ultrasound exam was performed to measure the Pulsatility Index of
Umbilical Artery, the Pulsatility Index of Middle Cerebral Artery and
the Amniotic Fluid Index. Ultrasound examination was performed with a
3.5-MHz sector ultrasound transducer with the high-pass filter set at
100 Hz, in a moment of absence of fetal breathing and body movements.
The umbilical artery, middle cerebral artery and uterine arteries were
studied using colour Doppler according to the most modern standard
protocol11Bhide A, Acharya G, Bilardo CM, Brezinka C, Cafici D,
Hernandez-Andrade E et al. ISUOG practice guidelines: use of Doppler
ultrasonography in obstetrics. Ultrasound Obstet Gynecol. 2013
Feb;41(2):233-39..
The CPR was calculated by dividing the Doppler indices of the middle
cerebral artery (MCA) by the umbilical artery (UA). The UA and MCA
pulsatility index (PI) was calculated according to a standard
protocol22Bahlmann F, Reinhard I, Krummenauer F, Neubert S,
Macchiella D, Wellek S. Blood flow velocity waveforms of the fetal
middle cerebral artery in a normal population: reference values from
18 weeks to 42 weeks of gestation. J Perinat Med 2002; 30: 490 – 501..
The maternal haemodynamics was assessed by UltraSonic Cardiac Output
Monitor (USCOM®, USCOM Ltd., Coffs Harbour, Australia). It is a
non-invasive method that uses a continuous-wave Doppler to determine CO.
It has demonstrated a comparable accuracy to invasive methods (Swan-Ganz
catheter) and the USCOM measurements are well correlated with
echocardiographic assessments33Bijl RC, Valensise H, Novelli GP,
Vasapollo B, Wilkinson I, Thilaganathan B et al; International Working
Group on Maternal Hemodynamics. Methods and considerations concerning
cardiac output measurement in pregnant women: recommendations of the
International Working Group on Maternal Hemodynamics. Ultrasound
Obstet Gynecol. 2019 Jul;54(1):35-50.,44Kager
CC, Dekker GA, Stam MC. Measurement of cardiac output in normal
pregnancy by a non- invasive two-dimensional independent Doppler
device. Aust N Z J Obstet Gynaecol. 2009 Apr;49(2):142-4.,55Namara
H, Barclay P, Sharma V. Accuracy and precision of the ultrasound
cardiac output monitor (USCOM 1A) in pregnancy: comparison with
three-dimensional transthoracic echocardiography. Br. J. Anaesth.
(2014) 113 (4): 669-676.. The measurements were performed by two
trained operators, in the same room, under standardised conditions, with
a patient in a semi-recumbent position, after she had rest in this
position at least 15 minutes. Blood pressure was obtained before the
hemodynamic measurement, using an automatic blood pressure monitor with
the patient in a semi-recumbent position and using an appropriately
sized cuff.
All the examinations were made from the suprasternal notch targeting the
aortic valve using a 2.2 MHz Transducer, with patients in left lateral
recumbent position.
We collected the following USCOM parameters: systolic blood pressure
(SBP), diastolic blood pressure (DBP), systemic vascular resistance
(SVR), systemic vascular resistance index (SVRI), cardiac output (CO),
cardiac index (CI), stroke volume (SV), Smith-Madigan inotropy index
(INO), flow time corrected (FTc), potential to kinetic energy ratio
(PKR).
At the day of childbirth, we collected information about the labor and
the delivery in order to identify any maternal or neonatal
complications: gestational age at time of delivery, request of epidural
analgesia, labor onset type (spontaneous or with induction), childbirth
type (spontaneous, operative vaginal delivery, c-section) and any
obstetrical indications, type of placental delivery, loss of blood and
need of blood transfusion, neonatal sex, neonatal weight, 1-min Apgar
and 5-min Apgar.
The induction of labor, if was required by internal routine antenatal
management protocols, was performed with dinoprostone 10 mg vaginal
insert and, after 24 hours, if the labor failed to start the vaginal
insert was removed and after 30 minutes the oxytocin infusion started
according to “low-dose” protocol66Fondazione Confalonieri
Ragonese su mandato di SIGO, AOGOI, AGU. Induzione al travaglio di
parto. 2016.
A delivery was considered “complicated” if just one of these
conditions was present:
- caesarean section or vaginal operative delivery for pathological
CTG77National Institute for Health and Care Excellence.
Interpretation of cardiotocograph traces, NICE guideline 2017.,
- major post-partum haemorrhage (PPH) with uterine atony,
- 5- min Apgar score < 7,
- NICU admission.
The PPH is defined as the loss of 500 ml or more of blood from the
genital tract within 24 hours of the birth of a baby88Mousa HA,
Blum J, Abou El Senoun G et al. Treatment for primary postpartum
haemorrage Cochrane Database Syst Rev2014;(2)CD003249
Mousa HA, Blum J, Abou El Senoun G, Shakur H, Alfirevic Z.
Treatment for primary postpartum haemorrhage. Cochrane
Database Syst Rev 2014;(2):CD003249.
Mousa HA, Blum J, Abou El Senoun G, Shakur H, Alfirevic Z.
Treatment for primary postpartum haemorrhage. Cochrane
Database Syst Rev 2014;(2):CD003249. The uterine atony is defined as
the condition when the uterus fails to contract after the delivery of
the baby99Breathnach F, Geary M. Uterine atony: definition,
prevention, nonsurgical management, and uterine tamponade. Semin
Perinatol. 2009 Apr;33(2):82-7.