Gebelikte Fizyolojik Değişiklikler
Özet
Gebelik, anne vücudunda fetüsün gelişimini desteklemek ve doğuma hazırlık sağlamak amacıyla anatomik, fizyolojik ve hormonal birçok değişimi beraberinde getirir. Uterus hacimsel olarak büyürken, utero-plasental kan akımı belirgin şekilde artar. Hematolojik sistemde plazma hacminin eritrosit artışından daha fazla genişlemesi fizyolojik anemiye yol açar. Protrombotik durum ve hafif lökositoz da bu dönemin karakteristik özelliklerindendir. Kardiyovasküler açıdan sistemik vasküler direnç düşer, kalp hızı ve kardiyak output artış gösterir. Solunum sisteminde dakika solunum hacmi ve tidal volüm artarken, progesteron kaynaklı hiperventilasyon hafif bir solunumsal alkaloza neden olur. Üriner sistemde glomerüler filtrasyon hızı (GFR) yaklaşık %50 artar, bu durum serum kreatinin düzeylerini düşürürken fizyolojik proteinüriye zemin hazırlar. Gastrointestinal sistemde progesteron etkisiyle bağırsak motilitesi yavaşlar, konstipasyon ve gastroözofageal reflü sıklığı artar. Endokrin sistemde ise hipofiz bezi büyür, prolaktin seviyeleri artar ve hCG'nin TSH ile benzerliğinden dolayı geçici bir subklinik hipertiroidizm tablosu gözlenebilir. Kas-iskelet sisteminde omurganın ağırlık merkezinin değişmesiyle lomber lordoz artar ve relaksin hormonu eklem hareketliliğini kolaylaştırır. Ciltte ise melazma ve stria gravidarum gibi pigmentasyon ve doku değişiklikleri en yaygın bulgulardır.
Pregnancy brings about numerous anatomical, physiological, and hormonal changes to support fetal development and prepare for childbirth. While the uterus expands significantly, utero-placental blood flow increases. In the hematological system, plasma volume expands more than erythrocyte mass, causing physiological anemia, while a prothrombotic state and mild leukocytosis are also characteristic. Cardiovascularly, systemic vascular resistance decreases, while heart rate and cardiac output rise. Respiratory changes include increased minute ventilation and tidal volume, with progesterone-driven hyperventilation causing mild respiratory alkalosis. In the urinary system, the glomerular filtration rate (GFR) increases by about 50%, lowering serum creatinine and predisposing to physiological proteinuria. The gastrointestinal system experiences reduced bowel motility due to progesterone, increasing constipation and gastroesophageal reflux. Endocrinologically, the pituitary gland enlarges, prolactin levels rise, and transient subclinical hyperthyroidism can occur due to hCG’s similarity to TSH. Musculoskeletally, the shifting center of gravity increases lumbar lordosis, and relaxin enhances joint mobility. Finally, cutaneous changes like melasma and stria gravidarum are common.
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