A cross-sectional study was conducted during the period of August 2008 to August 2010. Ethical clearance was sought from Institutional Ethical Committee. After acquiring informed consent, about 500 pregnant women who attended the Outpatient Department of Maternity Hospital, Madras Medical College, Chennai, Tamil Nadu, India during the time period were randomly selected, irrespective of the duration of pregnancy and gravidity. Pregnant women in active labour were excluded from the study. Detailed history and complete dermatological examination was done in all cases to study the physiological and pathological changes of skin and its appendages. Relevant systemic examination and investigations like KOH mount, Gram’s stain, Tzanck smear, and liver function test were done if required to confirm the diagnosis. Venereal Disease Research Laboratory (VDRL) and enzyme linked immune sorbent assay for Human Immunodeficiency Virus (HIV) were done in all the cases. Results were tabulated and analysed.

Statistical analysis of major cutaneous changes between primigravidas and multigravidas, and between various trimesters was done by Fisher’s-exact test and Chi-square test. Statistical analysis was done using software SPSS version 16. A p-value less than 0.05 were considered significant.

A total of 500 pregnant women were studied from August 2008 to August 2010. Of these, 291 (58.2%) were primigravidas, 209 (41.8%) were multigravidas. Among the multigravidas, 164 (32.8%) were second gravida, 39 (7.8%) were third gravida, and six (1.2%) were fourth gravida. Cases seen in the I^st trimester were nine (1.8%), II^nd trimester were 87 (17.4%) and III^rd trimester were 404 (80.8%).

The distribution of physiological skin changes observed during pregnancy (n =500) is shown in [Table/Fig-1].

Physiological skin changes were seen in about 474 cases (94.8%). Pigmentary changes were noticed in 454 cases (90.8%). Of the pigmentary changes, diffuse pigmentation was noted in 420 cases (84%). About 254 cases (50.8%) were primigravidas. About 369 cases (73.8%) were observed in III^rd trimester. The difference in proportion of pigmentary changes between primigravida and multigravida was statistically significant (p <0.001) and that between various trimesters was not statistically significant (p = 0.349), is shown in [Table/Fig-2,3]. Vascular changes were seen in 118 cases (23.6%), all were seen in III^rd trimester, the difference in proportion of vascular changes between various trimesters was statistically significant (p < 0.0001), is shown in [Table/Fig-4]. Connective tissue changes were observed in 402 cases (80.4%). Of these, striae gravidarum was seen in 398 cases (79.6%). The difference in proportion of striae gravidarum between primigravida and multigravida was statistically significant (p<0.0001) and between various trimesters was also statistically significant (p = 0.007), as shown in [Table/Fig-5,6] respectively.

The specific dermatoses of pregnancy were observed in 70 cases (14%) exclusively in III^rd trimester in this study, the distribution of cases were shown in [Table/Fig-7]. The difference in proportion of specific dermatoses between primigravida and multigravida was statistically significant (p<0.0001), and between various trimesters was also statistically significant (p<0.0001), is shown in [Table/Fig-8, 9] respectively. Pruritus gravidarum was the most common disease encountered (n=52, 10.4%), followed by prurigo of pregnancy (1.8%) and Pruritic Urticarial Papules and Plaques of Pregnancy (PUPPP) (1.6%).

The distribution of infections observed during pregnancy was shown in [Table/Fig-10]. The distribution of miscellaneous dermatoses observed during pregnancy was shown in [Table/Fig-11].

In our study, majority of the pregnant women had physiological skin changes (n=474, 94.8%). Hyperpigmentation is common during pregnancy and may be seen in up to 90% of pregnant women [1]. Kumari R et al., reported hyperpigmentation in 91.4% of pregnant women [2]. Muzaffar F et al., observed pigmentary changes in 90.7% of cases [3]. Fernandes LB et al., reported pigmentary changes in 87.95% of cases [4]. Panicker W et al., observed hyperpigmentation in 87.67% of cases [5]. In this study, we observed pigmentary changes in 90.8% which is consistent with above mentioned studies. The most common pigmentary change was diffuse pigmentation seen in 420 cases (84%). The sites of increased pigmentation observed in the order of frequency were areolae, genitalia, neck and axilla. Secondary areolae developed in all 420 cases (100%). In this study, linea nigra (LN) was seen in 186 cases (37.2%), whereas LN was observed as the most common pigmentary changes in studies conducted by Panicker W et al., (87.67%) and Hassan I et al., (80%) [5,6].

Melasma has been reported to occur in up to 70% of pregnant women [7]. Muzaffar F et al., found melasma to be present in 46.4% of their cases and Raj S et al., observed melasma in 8.8% of cases, whereas in this study, melasma was seen in 26% (n=130) of cases [3,8]. Cheeks and nose were the common sites involved. Martin AG et al., reported an onset of melasma during II^nd trimester, whereas in this study, the onset of melasma in most (n=98, 19.6%) of the cases were in early third trimester [9].

The increased prevalence of pigmentary changes may be related to elevated serum levels of melanocyte stimulating hormone, oestrogen and possibly progesterone [7].

Muzaffar F et al., reported vascular changes in 34.2% of cases, with non-pitting pedal oedema in 48.5% of cases [3]. In our study, vascular changes were noticed in 23.6% (n=118) of cases, with non-pitting pedal oedema in 16.4% of cases. Vascular changes were thought to be due to sustained high levels of circulating oestrogen resulting in distension and proliferation of vessels [10].

In III^rd trimester, higher proportion of vascular changes was observed (23.6%), which was statistically significant (p<0.0001), this may be due to increased venous pressures in the femoral and pelvic vessels caused by the gravid uterus.

Kumari R et al., Muzaffar F et al., Panicker W et al., and Raj S et al., reported striaegravidarum in 79.7%, 77.1%, 72.83% and 75.4% respectively [2,3,5,8]. In our study, the prevalence of striae gravidarum was found to be 79.6% (n=398) of cases, with the onset being more common during third trimester (n=330, 66%), which was statistically significant (p=0.007). In primigravidas, higher proportion of striae gravidarum was observed (40.8%), which was statistically significant (p<0.0001). Adrenocortical hormones, oestrogen, relax in and physical factors such as stretching secondary to an increase in the abdominal girth, might explain the prevalence of striae in III^rd trimester. There also seems to be an association between the maternal weight gain, foetal birth weight and the development of striae [7].

The changes in hair growth such as hirsutism (0.6%), telogen effluvium (1%) are in accordance with other studies [2].

Miliaria was observed in 13.6% (n=68) of cases. This may be due to the increased eccrine function during pregnancy.

Specific dermatoses of pregnancy are almost always associated with an eruption of variable severity and pruritus. It includes conditions that occur exclusively during pregnancy and results directly from the state of gestation or the products of conception. Kumari R et al., reported 22(3.6%) cases of specific dermatoses of pregnancy [2]. Fernandes LB et al., reported specific dermatoses in 8.72% of cases and Panicker W et al., reported specific dermatoses in 2% of cases [4,5].

Raj S et al., reported specific dermatoses in 16.3% of cases [8]. The specific dermatoses of pregnancy observed in our study was 14% (n=70) and was seen exclusively in third trimester, which was statistically significant (p<0.0001). This may be possible because in III^rd trimester placental hormonal levels will be highest and spontaneous remission occurs at delivery, when hormone concentrations normalize [1]. Higher proportion of specific dermatoses was observed in primigravida (11.6%), which was statistically significant (p<0.0001). Pruritus gravidarum (10.4%) was the most common disease observed in our study, whereas atopic eruption of pregnancy was the most common disease observed by Fernandes LB et al., (70.88%) and Hassan I et al., (50%) [4,6].

In literature, pruritus gravidarum is seen in the third trimester of pregnancy in 70% of cases, with the incidence varying from 0.02% to 2.4% of pregnancies [7,11]. Fernandes LB et al., reported 18.98% of cases of pruritus gravidarum [4]. Hassan I et al., reported 25% of cases of pruritus gravidarum [6].

In our study, PUPPP was observed in eight cases. Majority were primigravidas (1.4%). The parity (primigravida) and the onset in III^rd trimester is consistent with other studies [2,12]. Furthermore, the onset in III^rd trimester and the primigravida being affected more was supported by the hypothesis that rapid abdominal wall distension in primigravidas may cause damage to connective tissue in the striae with conversion of nonantigenic molecules to antigenic ones, triggering an inflammatory response [13,14].

Kumari R et al., Raj S et al., and Shivakumar V et al., reported prurigo of pregnancy in 0.16%, 1.2% and 9.41% of cases respectively [2,8,12]. In this study, prurigo of pregnancy was seen in 1.85% of cases. Pruritic folliculitis of pregnancy was noticed in 0.2%, which is consistent with other studies [2].

The infections observed in our study was 30.8%. Statistically significant proportion of infections were observed in multigravidas (15.4%, p=0.0142). The most common infection observed in our study was fungal infection, seen in 23.8%, followed by viral (4%), trichomoniasis (1.6%) and bacterial (1.2%) infections. Pityriasis versicolor was seen in 10.60% of cases, the high prevalence may be attributed to warm humid environment in addition to the influence of pregnancy [15]. Candidiasis was seen in 8% of cases, this may be due to the higher glycogen content in the vaginal environment and oestrogen mediated enhanced adherence of Candida species to vaginal epithelial cells resulting in an increased risk of symptomatic vaginitis in pregnancy [16]. The most prevalent viral infection was wart (1.6%). Accelerated viral replication with advanced pregnancy has been hypothesized. Certainly the moistness offered by vaginal mucus throughout pregnancy offers ideal moist conditions for viral growth [17]. The prevalence of HIV infection in pregnant women in India is about 0.3%. In our study, HIV was seen in 0.2% of cases. Pregnancy does not alter disease progression in asymptomatic women and those with early disease, although there may be a more rapid progression in women with late stage HIV infection [18]. Hansen’s disease was seen in 0.4% of cases. One had lepromatous leprosy and the other had borderline tuberculoid leprosy. Both the patients noticed the disease onset during pregnancy, which clearly shows the worsening of the disease during pregnancy, as described in literature [19].

Psoriasis was observed in one individual (0.2%), without any worsening during pregnancy, which is consistent with literature [20]. Impetigo herpetiformis was observed in 0.25 of cases (n=1) during III^rd trimester. The onset of the disease is consistent with other studies [7]. The patient was a known case of psoriasis vulgaris, who presented as generalized pustular psoriasis during pregnancy with typical features. As described in literature, this may be due to the hormonal influence of pregnancy over the disease, as an endocrine cause is being suspected for impetigo herpetiformis [10].

Exacerbation of neurofibromatosis with increased number of cutaneous neurofibromas during pregnancy in III^rd trimester was seen in two cases (0.4%). This is in accordance with literature, that neurofibroma may enlarge or arise de novo during pregnancy [7].

These three cases (0.6%) of systemic lupus erythematosus was observed with cutaneous flares and arthritis, which is consistent with literature. Complement activation is associated with disease flares during pregnancy [21].

This study lacks generalisation to the entire population of pregnant women because it was carried out in a tertiary health care centre. Further the study setting being a referral centre there is a possibility that the prevalence of the pregnancy specific dermatoses could have been over estimated.

In this study, the prevalence of physiological skin changes (94.8%) was much higher than specific dermatoses (14%), stressing the fact that in most instances, the skin problems during pregnancy needs only reassurance. But meticulous observation and examination should be done, as pregnancy can influence many dermatological diseases and infections.