**4. Urethral malformations**

The most common obstructive cause of the lower urinary tract is the posterior urethral valve (PUV). PUV is due to the existence of membranes in the posterior urethra. Echography shows dilated bladder and urethral dilatation, giving a classic echographic sign—'the keyhole sign'. Dystriation of ureters and troughs also occurs [14]. In advanced forms, oligohydramniosassociated pulmonary hypoplasia and urinary ascites may also appear. These fetuses require prenatal intervention to avoid kidney damage. Some authors tried to demonstrate that creating a vesicoamniotic passage may lead to a better outcome, but this has not yet been fully demonstrated [16].

In the prenatal life, other malformations may be seen:


**3. Bladder anomalies**

**Figure 8.** Ureterocele and hydroureter.

298 Congenital Anomalies - From the Embryo to the Neonate

lies and lesions, such as:

of the anterior abdominal wall.

The bladder is a very important element in antenatal fetal examination. Clinicians may suspect anomalies of the bladder when not visualized on prenatal examination or when enlarged.

**a.** Megacystis is a neurodysplastic disease, due to the anomaly of innervation. This leads to bladder dilatation (over 7 cm in diameter). It may be associated with small, short and dilated bowels, as well as a low-caliber colon. At ultrasound, the striking signs are polyhy-

**c.** Bladder exstrophy. It is commonly associated with other urogenital malformations and is constantly accompanied by epispadias. This pathology is characterized by many anoma-

• Lesions of the genitalia: micropenis and cryptorchidism appear in boys; in girls, the vagina is short and has various degrees of stenosis, the clitoris is bifid and the small labia are divergent. • The anterior bladder wall is absent, and the posterior wall is the submuscular segment

From the pathological point of view, we may encounter various anomalies as well:

dramnios, enlarged ureters and kidneys [17].

**b.** Congenital bladder diverticulitis. A septum can be observed.

• Abdominal anterior wall injuries: inguinal hernia is common.

• Lesion of pelvic bones: shortening and defects of rotation of pubic bones.

	- Balanic: distal incomplete defect.
	- Penian: incomplete proximal defect.
	- Penopubian: a complete defect, often associated with bladder exstrophy. In this situation, a distinct pathological condition appears: the exstrophy-epispadias complex [19].
	- Hypospadias: the anomaly is characterized by opening the urethra on the ventral side of the penis, at any level between the gland and the perineum, causing a ventral penis (chord). Patients with hypospadias have often abnormalities of the foreskin and cryptorchidic scrotum, inguinal hernia and hydrocele. Studies have shown a higher presence of hypospadias in patients with fetal growth restriction (**Figures 9** and **10**) [19]

follow-up and management of mild or moderate hydronephrosis observed during antenatal ultrasound examinations [15]. The prenatal diagnosis may improve the prognosis and the outcome of the fetus. An early diagnosis and treatment of urinary obstruction may prevent

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Most of the cases will spontaneously resolve after delivery. Thus, some assurance should be given. Many studies suggest follow-up when the AP diameter is 4–7 mm and antibiotic

The postnatal assessment of fetal hydronephrosis may be invasive and lengthy [6–8]. Thus, the risks and the inconvenience of a protracted evaluation need to be weighed against the probability that milder degrees of renal pelvic dilatation will decrease without resulting in

The spectrum of congenital genital malformation is very broad, and the diagnosis is usually

**3.** Female pseudohermaphroditism: adrenogenital syndrome or congenital adrenal hyper-

Fetal gender abnormality is diagnosed by ultrasound or by finding a discrepancy between fetal phenotype and sex chromosomes. The ultrasound diagnosis is late, usually accessible in

Due to improved ultrasound technology and increased experience in this area, the fetal sex can be established with high accuracy beyond 13 weeks of pregnancy [5]. Determination of fetal sex is based on the 'sagittal sign'. During the first trimester, in the sagittal plane, the penis is oriented upwards and the clitoris downwards. In the third trimester, the genitalia can be

difficult. A reliable classification reveals four main types of genital anomalies:

**1.** True hermaphroditism: an individual has both ovarian and testicular tissues.

the renal damage or loss of renal function [5, 21].

any renal damage [17].

**6. Congenital genital anomalies**

**2.** Male pseudohermaphroditism.

**4.** Gonadal dysgenesis [5, 19, 20].

**I.** Male genital malformations

described with high accuracy [21].

**1.** Micropenis or penian hypoplasia

**2.** Penian agenesis

Penian malformations (abnormal phallic structure)

**3.** Megalopenia or hyperplasia of the penis [1–3, 22]

the second or third trimesters [5, 20–24].

plasia. The main feature is clitoris hypertrophy.

therapy when the AP diameter is greater than 7 mm [14, 18].

**Figure 9.** Isolated megacystis: the right-side image is the sagittal plane of the fetus and the CRL (crown-rump length) measurement; the left-side image (same case) is the pathological specimen after medical termination of pregnancy.

**Figure 10.** Grade III hypospadias (perineal) is the most severe form, with the opening of the urethra at the penoscrotal junction.

The diagnosis of hypospadias with prenatal ultrasound is based on several important criteria:

