**5. Discussion**

Twin pregnancies have had a steady 70% increase since 1980 and are associated with increased perinatal mortality about 4 times higher than single pregnancies. The main cause of morbidity is preterm birth with an average birth of 35 weeks, the following are: intrauterine growth restriction, intrauterine death, hydramnio (about 10% of cases), preeclampsia (triple incidence in congenital pregnancies), congenital abnormalities, iron deficiency anemia, postpartum hemorrhage, placental abruption and precursor placenta [40–50].

Multiple pregnancies are high-risk pregnancies and are associated with increased neonatal morbidity and mortality, mainly due to prematurity. To understand how a multiple pregnancy increases the rates of adverse neonatal outcomes, it is necessary to record for each incident:


The successful use of assisted reproduction techniques is a milestone in the treatment of infertility. The increase of multiple pregnancies is a very important issue, open for solution, since they are accompanied by numerous medical and social problems. Preventing multiple pregnancies with the prudent use of available techniques will contribute significantly to solving this problem [6, 16].

Premature birth before 32–33 weeks of gestation is a major cause of complications in multiple pregnancies. The average age of spontaneous delivery is about 35.5 weeks while in multiple pregnancies it is 33 weeks. Premature birth occurs in 20–50% of twin pregnancies, which means 7–10 times more often compared to single pregnancies. The increased likelihood of twins' complications is mainly due to the high incidence of low birth weight infants as a result of premature or intrauterine growth restriction.

Prematurity is directly responsible for the high neonatal morbidity and mortality of twin pregnancies, due to the high probability of respiratory distress syndrome, intra-abdominal bleeding and necrotic enterocolitis. Also, there are increased rates of residual development of one fetus, or both of them, congenital abnormalities and complications associated with the Twin to twin Transfusion Syndrome (TTTS). Twin pregnancies complicated by premature birth burden the family financially and psychologically, because it requires the transfer of the pregnant woman or the newborn to tertiary hospitals, which have special intensive care units [58–65]. The incidence of depression is increased in mothers of twins, which requires special attention from the clinical doctor.

Newborns born from twin and triplet pregnancies are accompanied by the longterm consequences of perinatal complications. Cerebral palsy is the most common complication of multiple pregnancies. The rates of cerebral palsy are five times higher among twins and ten times higher among triplets, compared with other newborns. The case described in our study with persistent paraplegia was due to fetal hypoxia, cerebral palsy due to placental abruption in the 26th week of pregnancy [58–65].

A particularly important issue is the delivery time of a twin pregnancy and the growing tendency for premature termination of multiple pregnancies, as the increased tendency for preterm delivery in multiple pregnancies and the performance of premature cesarean section have significantly contributed to the increase in neonatal in multiple pregnancies. However, it is noteworthy that the selective neonatal decreases fetal mortality. The explanation for this lies in the fact that the duration of multiple pregnancies after a period of time increases the likelihood of endometrial death. In triplets, in particular, it is reported that after 34 weeks, fetal mortality increases significantly and requires close obstetric monitoring [65–68].

On the other hand, the preventive administration of corticosteroids as a routine, now, in all centers to enhance the pulmonary maturity of the fetus and the use of the surfactant, immediately after birth in premature infants, have the effect of drastically reducing deaths from respiratory distress syndrome in neonates of multiple pregnancies. There is evidence to suggest that the estimate of fetal weight of multiple pregnancies, with the growth curves created for single pregnancies, is incorrect.

#### *Twin Pregnancies Labour Modus and Timing DOI: http://dx.doi.org/10.5772/intechopen.95982*

Recent data from population studies show that optimal survival of neonates from multiple pregnancies is observed at a younger gestational age and lower body weight than in neonates of single pregnancies [68–70].

The developmental curves of the embryos used in the daily obstetric practice and in our country, are the result of the analysis of data from hospital databases, in non-European populations. According to studies, the distribution of fetal weight in relation to gestational age varies significantly, depending on the population and the time period. There is a difference of up to 11% in the average birth weight of newborns of different populations, at a certain gestational age, while the differences are even greater, exceeding 45% for the third percentage growth curve of the populations of these newborns [68–74].

Residual intrauterine development of fetal twin pregnancies is traditionally diagnosed using single growth curves from single pregnancies. Twins grow at rates similar to those of single pregnancies by the 30th week, followed by slower growth rates, while the same applies to the way triplets develop in relation to twins. Therefore, the developmental curves of the newborns should be revised and adjusted according to the number of fetuses and the gestational age, in order to become more rational.

Systematic monitoring of multiple pregnancies and the correct guidance of the doctor to the pregnant woman for a conservative lifestyle, are the cornerstone for avoiding prematurity. Ultrasound plays an irreplaceable role in the monitoring of multiple pregnancies, with the timely determination of the number of fetuses, the chorionic villus sampling, the position of the placenta and the continuous assessment of the development of the fetus in terms of weight [65–74].

In addition, the use of Doppler contributes to the early diagnosis of intrauterine growth disorders and fetal distress. The use of ultrasound in combination with cardiotocography and the systemic administration of corticosteroids, in all multiple pregnancies between 27 and 33 weeks, are the modern arsenal of the Obstetrician for the diagnosis and treatment of prematurity in these pregnancies. Also, the measurement of fetal fibronectin in the cervix, the ultrasound determination of the length of the cervix or the measurement of estradiol in the saliva of the pregnant woman, are techniques that are experimentally applied for the early diagnosis of premature birth [65–74].

Regarding the method of childbirth in multiple premature pregnancies, both worldwide and in our country, there is a tendency to increase caesarean sections, which is statistically significantly associated with a reduction in intrauterine deaths, single pregnancies. This risk is only 1% in a single pregnancy, while it increases by 10% in dichorionic twins and 15% in monochorionic twins, due to the occurrence of complications from placental anastomoses [65–74]. Therefore, measuring the length of the cervix during the ultrasound examination in the first and second trimester helps to prevent and properly treat impending prematurity. Twin pregnancies are high-risk pregnancies. The average gestational age for twins is about 35 weeks. Newborns of multiple pregnancies have a low birth weight, with an average of 2,500 g for twins. About 10% of twins and 25% of triplets have a birth weight of less than 1,500 g. Low birth weight results in high perinatal mortality, especially in monochorionic pregnancies accompanied by an increased rate of prematurity [65–74].

Multiple pregnancies resulting from infertility are at increased risk of preterm birth versus twin pregnancies with normal conception. This is due to pre-existing risk factors in women with a history of infertility such as uterine abnormalities pelvic infections surgery. Assisted reproduction methods increase monozygotic twins 12 times 13% after ovulation induction 22% for triplets with monozygotic twins. It is estimated that in multiple pregnancies the increased infant mortality is accompanied by almost twice the probability of severe neonatal disability compared to single pregnancies [65–74].

According to an analysis of the International Bibliography, they were certified at a high frequency of complications from fetuses, but the assessment of the above data should be done with consideration and strict criteria according to the guidelines.

Many researchers have found that along with the increase of pregnant's women age, there is a corresponding increase in the frequency of multiple pregnancies. Other researchers have found an increased incidence of multiple pregnancies in high births compared to first-borns, although the widespread use of assisted reproduction methods now tends to reduce this increase [65–74]. The large increase in the frequency of caesarean sections (41%) is one of the most dramatic changes in the last 40 years regarding the manner of delivery. This large increase is attributed to the fear of possible legal involvement and to the increased perinatal morbidity and mortality of the second neonate, especially when the shape is not vertical. Perinatal mortality has decreased in recent years, hovering internationally at 9.6% without a statistically significant difference between newborn twins [65–74]. An important contribution to the formation of perinatal mortality has the birth of multiple newborns weighing less than 1500gr. According to many researchers, no significant difference was found in the Apgar score between 1st and 2nd twins, as well as a relationship between the score and the way the childbirth was completed. According to others in twins born with a normal birth, the Apgar score of the 1st minute of the 2nd was lower compared to that of the 1st. There has also been a recent increase in the Apgar score, especially in the second duo indicative of a better perinatal outcome.

An important role in reducing perinatal mortality and improving perinatal status was played by the early diagnosis of multiple pregnancies in the last 20 years, as well as the systematic application of ultrasound and Doppler ultrasound in their monitoring [65–74]. The above resulted in a more accurate estimate of the probable birth weight, shape and projection, as well as the more correct design of the delivery arrangement.

The frequency of premature births and births of newborns weighing less than 2500gr. remains high despite the systematic application of tocolytic preparations and the restriction of activity until complete multiple immobility of pregnant women.

Regarding the way of arranging births in multiple pregnancies, a particularly statistically significant increase in the frequency of caesarean sections was observed in the last 5 years, amounting to 97.1% for the same reasons as described by internationally renowned researchers [65–74]. Regarding the application of biophysical methods of monitoring prenatal control in twin pregnancies of our study we found increased frequency of cardiotocographic lesions in the form of predominantly varying decelerations especially in the 2nd twin fetus and the above finding can be explained by the relatively high frequency of false positive cardiotocographic findings observed internationally.

The Apgar rating of twin pregnancies, as well as between 1st and 2nd newborn twins, clearly showed that the perinatal condition, especially of the 2nd newborn, was slightly aggravated. This finding contradicts that of many researchers, although many agree with our results without a satisfactory interpretation, possibly due to the frequently changing abnormal projection of the latter. We did not find a statistically significant difference in gender [65–74]. The perinatal mortality of twin pregnancies in our study did not differ significantly from that of the international literature, which confirms the significant improvement in recent years in the application of modern and accurate methods of diagnosis, monitoring of pregnancy and childbirth.
