Live birth

Colorectal Cancer. Colorectal cancer occurs frequently in the UK population but is historically rare in Asia. Rates in Japan have, however, increased rapidly in recent years.Interestingly, there appears to be an association between oestrogen exposure and colon cancer risk has been shown to increase in women with increasing age of first live birth, and to decrease with increasing parity (number of children). In addition, many colon tumours express sex hormone receptors, and this is thought to play a part in development of the tumours. "... 

Before starting an IV infusion of oxytocin for the induction of labor, the nurse obtains an obstetric history (parity, gravidity, previous obstetric problems, type of labor, stillbirths, abortions, live birth infant abnormalities)... 

While the overall population Incidence of trisomy 21 Is between 1 In 700 and 1 In 600 live births (48, 49), the frequency of Its appearance In any given family Is determined by two factors. 

Figure 3.2 Infant mortality rates (IMR) per 1 000 live births ...

The mean maternal age for the 12 mothers included in this study was 25.8 years, with a range of 20 to 31 years. Mother s race was 75 percent black, 17 percent white, and 8 percent Hispanic. All were low income. Eighty-three percent of the women were multiparas with an average of 5.2 previous pregnancies and 2.7 live births. 

Lubchenco, L.O. Hansman, C. and Boyd. E. Intrauterine growth in length and head circumference as estimated from live births at gestational ages from 26 to 42 weeks. Pedi at.ri cs 37 404-408, 1966. 

Recombinant DNase preparations have been used in the treatment of cystic fibrosis since the end of 1993. This genetic disorder is common, particularly in ethnic groups of northern European extraction, where the frequency of occurrence can be as high as 1 in 2500 live births. A higher than average incidence has also been recorded in southern Europe, as well as in some Jewish and African-American populations. 

In many localities, newborn screening has become standard for this disorder, which in the general population has an approximate incidence of 1/250,000 live births. Carrier detection is possible, either by measurement of enzymatic activity in cultured fibroblasts or by study of restriction endonuclease fragments of DNA. Antenatal testing is also available. 

Phenylketonuria usually is caused by a congenital deficiency of phenylalanine hydroxylase. Phenylketonuria (PKU) is among the more common aminoacidurias (-1 20,000 live births). The usual cause is a nearly complete deficiency of phenylalanine hydroxylase, which converts phenylalanine into tyrosine (Fig. 40-2 reaction 1). 

Aneuploidy in live births and abortions arises from aneuploid gametes during germ cell meiosis. Trisomy or monosomy of large chromosomes leads to early embryonic death. Trisomy of the smaller chromosomes allows survival but is detrimental to the health of an affected person, for example, Down s syndrome (trisomy 21), Patau syndrome (trisomy 13) and Edward s syndrome (trisomy 18). Sex chromosome trisomies (Klinefelter s and XXX syndromes) and the sex chromosome monosomy (XO), known as Turner s syndrome, are also compatible with survival. 

The incidence of a gene mutation or a genetic disorder is the number of people who are born with the mutation or disorder in a specified group per year. Incidence is often written in the form "1 in [a number]" or as a total number of live births. 

Sickle cell disease is an autosoinal recessive disorder seen in approximately 1/600 African American births. It is even more common in some parts of Africa, vrftere up to 1/50 live births are affected. 

This chapter reviews diseases that are caused by microscopically observable alterations in chromosomes. These alterations may involve the presence of extra chromosomes or the loss of chromosomes. They may also consist of structural alterations of chromosomes. Chromosome abnormalities are seen in approximately 1 in 150 live births and are the leading known cause of mental retardation. The vast majority of chromosome abnormalities are lost prenatally chromosome abnormalities are seen in 50% of spontaneous fetal tosses during the first trimester of pregnancy, and they are seen in 20% of fetuses lost during the second trimester. Thus, chromosome abnormalities are the leading known cause of pregnancy loss. 

Triploidy refers to cells that contain three copies of each chromosome (69 total). THploidy, which usually occurs as a result of the fertilization of an ovum by two sperm cells, is common at conception, but the vast majority of these conceptions are lost prenatally. However, about 1 in 10,000 live births is a triploid. These babies have multiple defects of the heart and central nervous system, and they do not survive. 

Tetraploidy refers to cells that contain four copies of each chromosome (92 total). This lethal condition is much rarer than triploidy among live births only a few cases have been described. 

Trisomy 13 (Patau syndrome, 47,XY,+13 47,XX,H 13) is seen in approximately 1 in 10,000 live births. More than 90% of conceptions are lost prenatally, and more than 90% of those who survive to term do not survive to 1 year of age. Common disease features include oral-facial clefts, microphthalmia (small eyes), renal defects, and polydactyly (extra fingers). Central nervous system malformations and heart defects are common and contribute to mortality. 

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