**11. Amniotic fluid**

**9. Extremities**

or amniotic band constriction [54].

14 Congenital Anomalies - From the Embryo to the Neonate

**10. Placenta, umbilical cord**

after a previous cesarean section [56, 57].

position to the cervix) and morphology of the placenta [55].

**Figure 5.** Club-foot. On the picture the affected foot is rotated internally.

Congenital malformations of the extremities may appear as solitaire anomalies or as multiplex abnormalities associated with syndromes. Most of these malformations are hard to diagnose prenatally, the sensitivity of ultrasound is around 25% [50, 51]. Measurements of the

Club-foot (**Figure 5**) is the most prevalent congenital malformation of the extremities with a birth prevalence of 1:1000. However, according to some studies, the malformation occurs in 1:250 in utero [54]. The affected foot is rotated internally. In half of the cases, both feet are affected and club-foot is associated with other abnormalities (such as Trisomy 18). Also, it may occur as part of the Potter-sequence, or in neuromuscular anomalies, neural tube defects

In our study, malformations of the skeleton were diagnosed with a higher sensitivity than anomalies of the extremities (82.93% vs. 37.5%). We found higher ultrasound sensitivity in osteogenesis imperfecta (80%), reduction deformities (64.71%), and club foot (51.43%). Ultrasound was less effective in diagnosing hip dysplasia and malformations of the fingers.

The placenta is the organ that connects the mother to the fetus and ensures the normal development and growth of the fetus. It is important to examine the location (especially the relative

Placenta praevia is an anomaly when the placenta is inserted either partially or totally in the lower, passive segment of the uterus. It can only be diagnosed after the second trimester because the site of insertion usually shifts upwards with the growth of the uterus. Placenta praevia has a birth prevalence of 2.8:1000 and it is more common in twin pregnancies and

length of the femur and the humerus are part of the fetal biometry [52, 53].

The amniotic fluid is made by the placenta and the membranes before 16–18 weeks, while after 16 weeks, fetal kidneys gradually takes over the production up until birth. Kidneys excrete around 5 ml/h of urine after 20 weeks, which increases to 50 ml/h by the end of pregnancy. Abnormal quantity of the amniotic fluid may indicate a congenital malformation or chromosomal abnormality. Amniotic fluid index (AFI) is an objective method for determining the amount of the amniotic fluid. In the "four quadrant technique," the vertical length of each pocket of fluid is measured in each of the four quadrants and then the measurements are summarized. A normal AFI is 8–24 cm after 16 weeks of gestation. The other technique is the "single deepest pocket" technique measures the vertical length of the deepest pocket with a normal value of 2–8 cm. The latter is mostly used in twin pregnancies [57, 58].

Oligohydramnios is the condition when there is less amniotic fluid than the normal (less than 500 ml in the third trimester).

Types based on pathophysiology:


The fundus height is lower than normal and the fetal movements are dim, often painful. The AFI is less than 7 cm with the "four quadrant technique" and less than 2 cm measured in the deepest quadrant. Anhydramnios is the condition when the amniotic fluid is missing. Severe oligohydramnios may result in Potter sequence in the fetus. When oligohydramnios is caused by bilateral renal agenesis, the condition is called Potter-syndrome. In the third trimester, uterine contractions may result in the compression of the placenta and umbilical cord, endangering the fetus. Prenatal mortality in oligohydramnios is around 10% [58].

**References**

2011;**31**:7-15

175-192

[1] Nicolaides KH. Screening for fetal aneuploidies at 11 to 13 weeks. Prenatal Diagnosis.

Congenital Fetal Anomalies and the Role of Prenatal Ultrasound

http://dx.doi.org/10.5772/intechopen.71907

17

[3] Borrell A, Mercade I, Casals E, Borobio V, Seres A, Soler A, Fortuny A, Cuckle H.Combining fetal nuchal fold thickness with second-trimester biochemistry to screen for trisomy 21.

[4] Examination of the fetal cranium. In: Hobbins JC, editor. Obstetric Ultrasound: Artistry

[5] Cunningham FG, Leveno KJ, Bloom SL, Hauth JC, Rouse DJ, Spong CY. Fetal imaging. In: Williams Obstetrics. New York: The McGraw-Hill Companies Inc; 2010. pp. 349-371 [6] Fadda GM, Capobianco G, Balata A, Litta P, Ambrosini G, D'Antona D, Cosmi E, Dessole S. Routine second trimester ultrasound screening for prenatal detection of fetal malformations in Sassari University Hospital, Italy: 23 years of experience in 42,256 pregnancies. European

Journal of Obstetrics, Gynecology, and Reproductive Biology. 2009;**144**(2):110-114

[7] Levi S, Hyjazi Y, Schaapst JP, Defoort P, Coulon R, Buekens P. Sensitivity and specificity of routine antenatal screening for congenital anomalies by ultrasound: The Belgian Multicentric

[8] Tóth Z. A magzat craniospinalis rendellenességei. In: Tóth Z, Papp Z, editors. Szülészet-Nőgyógyászati Ultrahang-Diagnosztika. Budapest: White Golden Book Kft.; 2006. pp.

[9] Papp Z. A szülészet-nőgyógyászat tankönyve. Budapest: Semmelweis Kiadó; 2007

[10] Copp AJ, Stanier P, Greene ND. Neural tube defects: Recent advances, unsolved ques-

[11] De Keersmaecker B, Claus F, De Catte L. Imaging the fetal central nervous system. Facts,

[12] Boyd PA, Devigan C, Khoshnood B, Loane M, Garne E, Dolk H, EUROCAT Working Group. Survey of prenatal screening policies in Europe for structural malformations and chromosome anomalies, and their impact on detection and termination rates for neural tube defects and Down's syndrome. BJOG: An International Journal of Obstetrics and

[13] Cameron M, Moran P. Prenatal screening and diagnosis of neural tube defects. Prenatal

[14] Whitlow BJ, Chatzipapas IK, Lazanakis ML, Kadir RA, Economides DL. The value of sonography in early pregnancy for the detection of fetal abnormalities in an unselected

population. Journal of Obstetrics and Gynaecology. 1999;**106**(9):929-936

[2] Nicolaides KH. The 11-13+6 Weeks Scan. London: Fetal Medicine Foundation; 2004

Ultrasound in Obstetrics & Gynecology. 2007;**30**(7):941-945

in Practice. Oxford, UK: Blackwell Publishing Ltd; 2008. pp. 44-60

Study. Ultrasound in Obstetrics & Gynecology. 1991;**1**(2):102-110

tions, and controversies. Lancet Neurology. 2013;**12**(8):799-810

Views & Vision in ObGyn. 2011;**3**(3):135-149

Gynaecology. 2008;**115**(6):689-696

Diagnosis. 2009;**29**(4):402-411

Polyhydramnios is an excess of amniotic fluid around the fetus, more than 2000 ml in the third trimester. It occurs in 1–2% of pregnancies.

Types based on pathophysiology:


The fundus height is usually bigger than normal, the abdomen is large and tense. Mothers usually have dyspnea and the fetal heart sounds are faint. On ultrasound, a large echoless space can be seen between the fetus and the uterine wall with the umbilical cord freely floating. The polyhydramnios is mild when the vertical measurement of the deepest pocket is 8–11 cm, and severe when it is over 16 cm. AFI is usually more than 24 cm in the four quadrants. Cytogenetic examination is needed when polyhydramnios is associated with growth retardation as it may suggest chromosomal abnormality [57, 58].
