*3.3.2.1 Primiparous*

The idea that primiparous women have a greater risk of having offspring with DDH due to greater strength of the uterine musculature has been strengthened, which upon contracting will generate greater pressure in the product, but possibly also, due to the fact of a narrower intrauterine cavity [11].

*Diagnosis of Developmental Dysplasia of the Hip in Newborns and Infants DOI: http://dx.doi.org/10.5772/intechopen.104085*

#### *3.3.2.2 Nutrition*

Maternal alcoholism has been invoked as a risk factor for DDH [11, 15] and in canine animal models, some dietary factors that favor DDH and the severity of it have been reported [16]. Excessive caloric intake leads to rapid growth and early overload of the bone system and causes an increase in the frequency and severity of DDH in genetically susceptible dogs during the first 6 months of life [16, 28].

It has also been pointed out that elevated serum levels of vitamin C could decrease the frequency of DDH [16], but controlled studies could not demonstrate this [29]. Excessive consumption of vitamin D increases intestinal absorption and renal calcium reabsorption, and this may increase the risk of DDH in canine models [16]. This has led to a tendency to increase the frequency of DDH in the cold months [30–32] but this does not happen in Finland where the highest frequency was in the months of June and July [33].

Smoking has also been reported as a risk factor for DDH [16].

### *3.3.3 Macroenvironment*

#### *3.3.3.1 Swaddling or excessive clothing*

Excessive clothing has been reported as a risk factor in DDH [9, 11]; Mendoza-Lara et al., reported a strong association (P < 0.0004) of swaddling with the pelvic extremities in extension and adduction, with DDH [24]. This has led to a tendency to increase the frequency of DDH in the cold months [30–32] but this does not happen in Finland where the highest frequency was in the months of June and July [33].

#### *3.3.3.2 Pull on the hip*

Obstetric trauma, traction on the hips to extract a product in breech presentation, hold the neonate, after birth, of the heels without support in the back, can cause elongation of the ligaments of the hip and cause DDH [11, 16].
